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Interfacial issues between the perovskite film and electron transport layer greatly limit the efficiency and stability of inverted (p‐i‐n) perovskite solar cells (PSCs). Despite organic ammonium passivants have been widely established as interfacial layers, they failed to improve electron extraction. Here, we reported that the heavy n‐type characteristics in a low band gap perovskite film could be modulated by incorporating non‐conjugated ammonium passivants with strong electron‐withdrawing abilities. This resulted in a significant enhancement of electron extraction in the heavily n‐type doped perovskite. The passivant‐treated PSCs exhibited a power conversion efficiency of 25.74 % with an excellent fill factor of 85.4 % and a high open‐circuit voltage of 1.166 V, which are significantly higher than that of the control device. The unencapsulated devices maintained 88 % of their initial PCEs after 1,200 hours at 85 °C. [ABSTRACT FROM AUTHOR]

C60 is a widely used electron selective material for p–i–n perovskite cells, however, its energy level does not match well with that of a wide‐bandgap perovskite, resulting in low open‐circuit voltage (VOC) and fill factor (FF). To overcome this issue, ultra‐thin LiF has been widely used as an interlayer between C60 and perovskite layers facilitating efficient electron extraction but resulting in instability. In this work, the use of a piperidinium bromide (PpBr) is reported as an interlayer between C60 and perovskite, and the interlayer further is optimized by introducing an additional oxygen atom on the opposite side of the NH2+. This results in morpholinium bromide (MLBr) with increased dipole moment. Because of this, MLBr is highly effective in minimizing the energy band mismatch between perovskite and C60 layer for electron extraction while at the same time passivating defects. The champion single junction 1.67 eV MLBr solar cell produced a PCE of 21.9% and the champion monolithic MLBr perovskite‐Si tandem cell produced a PCE of 28.8%. Most importantly, both encapsulated MLBr and PpBr devices retain over 97% of their initial efficiency after 400 thermal cycles (between −40 and 85 °C), twice the number of cycles specified by the International Electrotechnical Commission (IEC) 61215 photovoltaic module standard. [ABSTRACT FROM AUTHOR]

Copyright of Technisches Messen is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tin oxide (SnO2) has demonstrated significant potential as an electron transport layer (ETL) owing to its low‐temperature processing in perovskite solar cells (PSCs). However, the poor energy‐level alignment and the presence of interface defects between the SnO2 and perovskite layer aggravate the power conversion efficiency (PCE) of the PSCs. Herein, heterovalent samarium cation (Sm3+) is deliberately doped into SnO2, optimizing the energy‐level alignment between SnO2 and the perovskite layer, and effectively passivating the oxygen vacancy defects on the surface of SnO2. Experimental and theoretical conclusions reveal that Sm‐doping successfully passivates the defects in the ETL and improves the perovskite crystal quality, thereby reducing interface charge recombination, and enhancing electron extraction from perovskite to the SnO2 layer. Consequently, the optimized Sm‐doped SnO2‐based PSCs achieve a PCE of 24.10% with a VOC of 1.174 V, negligible hysteresis, and improved durability under ambient conditions. [ABSTRACT FROM AUTHOR]

The cathode interlayer is crucial for the development of organic solar cells (OSCs), but the research on simple and efficient interlayer materials is lagging behind. Here, a donor‐acceptor (D–A) typed selenophene‐fused perylene diimide (PDI) derivative (SePDI3) is developed as cathode interlayer material (CIM) for OSCs, and a non‐fused PDI derivative (PDI3) is used as the control CIM for comparison. Compared to PDI3, SePDI3 shows a stronger self‐doping effect and better crystallinity, resulting in better charge transport ability. Furthermore, the interaction between SePDI3 and L8‐BO can form an efficient extraction channel, leading to superior charge extraction behavior. Finally, benefitting from significantly enhanced charge transport and extraction capacity, the SePDI3‐based device displays a champion PCE of 19.04 % with an ultrahigh fill factor of 81.65 % for binary OSCs based on PM6 : L8‐BO active layer, which is one of the top efficiencies reported to date in binary OSCs based novel CIMs. Our work prescribes a facile and effective fusion strategy to develop high‐efficiency CIMs for OSCs. [ABSTRACT FROM AUTHOR]

The electron extraction from perovskite/C60 interface plays a crucial role in influencing the photovoltaic performance of inverted perovskite solar cells (PSCs). Here, we develop a one‐stone‐for‐three‐birds strategy via employing a novel fullerene derivative bearing triple methyl acrylate groups (denoted as C60‐TMA) as a multifunctional interfacial layer to optimize electron extraction at the perovskite/C60 interface. It is found that the C60‐TMA not only passivates surface defects of perovskite via coordination interactions between C=O groups and Pb2+ cations but also bridge electron transfer between perovskite and C60. Moreover, it effectively induces the secondary grain growth of the perovskite film through strong bonding effect, and this phenomenon has never been observed in prior art reports on fullerene related studies. The combination of the above three upgrades enables improved perovskite film quality with increased grain size and enhanced crystallinity. With these advantages, C60‐TMA treated PSC devices exhibit a much higher power conversion efficiency (PCE) of 24.89 % than the control devices (23.66 %). Besides, C60‐TMA benefits improved thermal stability of PSC devices, retaining over 90 % of its initial efficiency after aging at 85 °C for 1200 h, primarily due to the reinforced interfacial interactions and improved perovskite film quality. [ABSTRACT FROM AUTHOR]

Colloidal quantum dots (CQDs) are promising optoelectronic materials for solution‐processed thin film optoelectronic devices. However, the large surface area with abundant surface defects of CQDs and trap‐assisted non‐radiative recombination losses at the interface between CQDs and charge‐transport layer limit their optoelectronic performance. To address this issue, an interface heterojunction strategy is proposed to protect the CQDs interface by incorporating a thin layer of polyethyleneimine (PEIE) to suppress trap‐assisted non‐radiative recombination losses. This thin layer not only acts as a protective barrier but also modulates carrier recombination and extraction dynamics by forming heterojunctions at the buried interface between CQDs and charge‐transport layer, thereby enhancing the interface charge extraction efficiency. This enhancement is demonstrated by the shortened lifetime of carrier extraction from 0.72 to 0.46 ps. As a result, the resultant PbS CQD solar cells achieve a power‐conversion‐efficiency (PCE) of 13.4% compared to 12.2% without the heterojunction. [ABSTRACT FROM AUTHOR]

Over the last few years, considerable efforts have been invested in designing solar cell modules that are envisaged to revolutionize photovoltaic technology towards clean and sustainable energy. Solid-state dye-sensitized solar cells (ssDSSCs) have gained considerable attention because of their robust light harvesting capabilities. Herein, we investigate the performance of a hole transport layer-free (HTL-free) ssDSSC architecture of the configuration ITO/PC61BM/N719 Dye/Ni HTL-free by device simulation using the solar cell capacitance simulator (SCAPS-1D). The results show viable power conversion efficiency (PCE) of 14.51%, coupled with an impressive fill factor (FF) of 84.58%, indicative of effective charge extraction mechanisms and minimal recombination losses within the device structure. Furthermore, the short-circuit current density (Jsc) and open-circuit voltage (Voc) attained remarkable values of 22.37 mA/cm2 and 0.7665 V, respectively. This work also found that the optimal defect density of the absorber was 1.0 × 1014 cm−3, whereas the optimal donor and acceptor densities were 1.0 × 1016 cm−3 and 1.0 × 1019 cm−3, respectively. These findings underscore the excellent light absorption, efficient charge generation, and good electron–hole separation at device interfaces. The findings of this work accentuate the promise of HTL-free ssDSSCs as high-performing solar cells characterized by simplified device architectures. The elimination of the HTL not only streamlines fabrication processes but also imparts cost efficiencies and enhances device stability. This study thus contributes invaluable insights to the advancement of efficient and commercially viable ssDSSCs, thereby inspiring progress towards a greener and more sustainable renewable energy landscape. [ABSTRACT FROM AUTHOR]

Abstract Fullerene derivatives are highly attractive materials in solar cells, organic thermoelectrics, and other devices. However, the intrinsic low electron mobility and electrical conductivity restrict their potential device performance, such as perovskite solar cells (PSCs). Herein, we successfully enhanced the electric properties and morphology of phenyl‐C61‐butyric acid methyl ester (PCBM) by n‐doping it with a benzimidazoline derivative, 9‐(1,3‐dimethyl‐2,3‐dihydro‐1H‐benzoimidazol‐2‐yl)‐julolidine (JLBI‐H) via a solution process. We found the n‐doping can not only improve the conductivity and optimize the band alignment but also enable the PCBM to have a constantly strong charge extraction ability in a wide temperature from 173 to 373 K, which guarantees a stable photovoltaic performance of the corresponding PSCs under a wide range of operating temperatures. With the JLBI‐H‐doped PCBM, we improved the efficiency from 17.9% to 19.8%, along with enhanced stability of the nonencapsulated devices following the aging protocol of ISOS‐D‐1.

Abstract Colloidal quantum dots (CQDs) are promising optoelectronic materials for solution‐processed thin film optoelectronic devices. However, the large surface area with abundant surface defects of CQDs and trap‐assisted non‐radiative recombination losses at the interface between CQDs and charge‐transport layer limit their optoelectronic performance. To address this issue, an interface heterojunction strategy is proposed to protect the CQDs interface by incorporating a thin layer of polyethyleneimine (PEIE) to suppress trap‐assisted non‐radiative recombination losses. This thin layer not only acts as a protective barrier but also modulates carrier recombination and extraction dynamics by forming heterojunctions at the buried interface between CQDs and charge‐transport layer, thereby enhancing the interface charge extraction efficiency. This enhancement is demonstrated by the shortened lifetime of carrier extraction from 0.72 to 0.46 ps. As a result, the resultant PbS CQD solar cells achieve a power‐conversion‐efficiency (PCE) of 13.4% compared to 12.2% without the heterojunction.

Carbon‐based hole transport material (HTM)‐free perovskite solar cells (CPSCs) are an innovative device architecture that mitigates inherent challenges associated with record‐breaking perovskite solar cells (PSCs), which rely on metal/HTMs, including instability, manufacturing intricacy, and elevated costs. The photovoltaic efficiency and stability of CPSCs are profoundly influenced by the charge carrier dynamics at the interfaces. Herein, the charge carrier dynamics at the carbon(C)–perovskite interface in CPSCs and its implications on photovoltaic performances and stability, an aspect that has received limited exploration thus far are probed, are investigated using transient surface photovoltage (Tr‐SPV) and transient photoluminescence measurements. The study reveals that the C‐electrode effectively acts as a selective barrier, impeding electrons while facilitating the extraction of holes at the C–perovskite interface. This selective blocking mechanism holds significant implications for improving the performance and stability of CPSCs over HTM‐free PSCs with gold(Au) electrodes. The stability of CPSCs is evaluated by measuring shelf life, maximum power point tracking, Tr‐SPV, and X‐Ray diffraction measurements. By delving into these pivotal aspects, this work aims to contribute to the advancement and understanding of CPSCs for sustainable and efficient energy conversion. [ABSTRACT FROM AUTHOR]

In this article, a combination of spherical and oval NiO nanoparticles were synthesized through the co-precipitation method and incorporated into a MAPbI3-based perovskite layer (MAPbI3:NiO) to enhance hole extraction in carbon-based perovskite solar cells (CPSCs). Field-emission scanning electron microscopy (FESEM) images of the MAPbI3 and MAPbI3:NiO NPs composite layers confirmed the formation of needle-like grains. The incorporation of NiO NPs in the perovskite layer enhanced both the crystallinity and the grain size of the film. Moreover, the NiO composited films showed maximum absorbance in the visible region and significantly quenched emission peak in the photoluminescence (PL) emission spectrum. Because of the materials' outstanding characteristics, the NiO composite perovskite device achieved power conversion efficiency (PCE) of 9.75%. In addition, the effect of adding a spacer layer in the same device architecture was also studied. The results showed an enhancement of the open-circuit voltage (Voc) from 862 mV to 988 mV, making the device a champion with PCE of ~11%. [ABSTRACT FROM AUTHOR]

Understanding the kinetic competition between charge extraction and recombination, and how this is impacted by mobile ions, remains a key challenge in perovskite solar cells (PSCs). Here, this issue is addressed by combining operando photoluminescence (PL) measurements, which allow the measurement of real‐time PL spectra during current–voltage (J–V) scans under 1‐sun equivalent illumination, with the results of drift‐diffusion simulations. This operando PL analysis allows direct comparison between the internal performance (recombination currents and quasi‐Fermi‐level‐splitting (QFLS)) and the external performance (J–V) of a PSC during operation. Analyses of four PSCs with different electron transport materials (ETMs) quantify how a deeper ETM LUMO induces greater interfacial recombination, while a shallower LUMO impedes charge extraction. Furthermore, it is found that a low ETM mobility leads to charge accumulation in the perovskite under short‐circuit conditions. However, thisalone cannot explain the remarkably high short‐circuit QFLS of over 1 eV which is observed in all devices. Instead, drift‐diffusion simulations allow this effect to be assigned to the presence of mobile ions which screen the internal electric field at short‐circuit and lead to a reduction in the short‐circuit current density by over 2 mA cm−2 in the best device. [ABSTRACT FROM AUTHOR]

The cathode interlayer plays a vital role in organic solar cells, which can modify the work function of electrodes, lower the electron extraction barriers, smooth the surface of the active layer, and remove solvent residuals. However, the development of organic cathode interlayer lags behind the rapidly improved organic solar cells because their intrinsic high surface tension can lead to poor contact with the active layers. Herein, a double‐dipole strategy is proposed to enhance the properties of organic cathode interlayers, which is induced by incorporating nitrogen‐ and bromine‐containing interlayer materials. To verify this approach, the state‐of‐the‐art active layer composed of PM6:Y6 and two prototypical cathode interlayer materials, PDIN and PFN‐Br is selected. Using the cathode interlayer PDIN: PFN‐Br (0.9:0.1, in wt.%) in the devices can reduce the electrode work function, suppress the dark current leakage, and improve charge extractions, leading to enhanced short circuit current density and fill factor. The bromine ions tend to break from PFN‐Br and form a new chemical bond with the silver electrode, which can adsorb extra dipoles directed from the interlayer to silver. These findings on the double‐dipole strategy provide insights into the hybrid cathode interlayers for efficient non‐fullerene organic solar cells. [ABSTRACT FROM AUTHOR]

Abstract The cathode interlayer plays a vital role in organic solar cells, which can modify the work function of electrodes, lower the electron extraction barriers, smooth the surface of the active layer, and remove solvent residuals. However, the development of organic cathode interlayer lags behind the rapidly improved organic solar cells because their intrinsic high surface tension can lead to poor contact with the active layers. Herein, a double‐dipole strategy is proposed to enhance the properties of organic cathode interlayers, which is induced by incorporating nitrogen‐ and bromine‐containing interlayer materials. To verify this approach, the state‐of‐the‐art active layer composed of PM6:Y6 and two prototypical cathode interlayer materials, PDIN and PFN‐Br is selected. Using the cathode interlayer PDIN: PFN‐Br (0.9:0.1, in wt.%) in the devices can reduce the electrode work function, suppress the dark current leakage, and improve charge extractions, leading to enhanced short circuit current density and fill factor. The bromine ions tend to break from PFN‐Br and form a new chemical bond with the silver electrode, which can adsorb extra dipoles directed from the interlayer to silver. These findings on the double‐dipole strategy provide insights into the hybrid cathode interlayers for efficient non‐fullerene organic solar cells.

[Display omitted] Narrow-bandgap mixed Sn-Pb perovskite solar cells (PSCs) have showcased great potential to approach the Shockley-Queisser limit. Nevertheless, the practical application and long-term deployment of mixed Sn-Pb PSCs are still largely impeded by the rapid oxidation of Sn2+ ions and under-optimized carrier transport layer (CTL)/perovskite interfaces that would inevitably incur serious interfacial charge recombination and device performance degradation. Herein, we successfully removed the hole transport layer (HTL) by incorporating a small amount of organic phosphonic acid molecules into perovskites, which could preferably interact with Sn2+ ions (relative to Pb2+ analogues) at the grain boundaries (GBs) throughout the perovskite film thickness via coordination bonding, thus effectively retarding the oxidation of Sn2+, passivating the defects and suppressing the non-radiative recombination. Targeted modification effectively reinforced built-in potential by ∼100 mV, and favorably induced energy level cascade, thus accelerating spatial charge separation and facilitating the hole extraction from perovskite layer to underlying conductive electrodes even in the absence of HTL. Consequently, enhanced power conversion efficiencies up to 20.21% have been achieved, which is the record efficiency for the HTL-free mixed Sn-Pb PSCs, accompanied by a decent photovoltage of 0.87 V and improved long-term stability over 2400 h. [ABSTRACT FROM AUTHOR]

Arising from the multiple light scattering sites, the regulation on perovskite film growth, Type-II band alignment and matched lattice spacing of 3D round-comb Fe 2 O 3 @SnO 2 composites, the light harvesting and charge extraction are significantly improved, which helps the CsPbBr 3 PSCs achieve a champion PCE of 10.23 % and excellent moisture tolerance. [Display omitted] The precise design of an electron transport layer (ETL) to improve the light-harvesting and quality of perovskite (PVK) film plays a crucial role in the photovoltaic performance of n-i-p perovskite solar cells (PSCs). In this work, a novel three-dimensional (3D) round-comb Fe 2 O 3 @SnO 2 heterostructure composites with high conductivity and electron mobility induced by its Type-II band alignment and matched lattice spacing is prepared and employed as an efficient mesoporous ETL for all-inorganic CsPbBr 3 PSCs. Arising from the multiple light scattering sites provided by the 3D round-comb structure, the diffuse reflectance of Fe 2 O 3 @SnO 2 composites is increased to improve the light absorption of the deposited PVK film. Besides, the mesoporous Fe 2 O 3 @SnO 2 ETL affords not only more active surface for sufficient exposure to the CsPbBr 3 precursor solution but also a wettable surface to reduce the barrier for heterogeneous nucleation, which realizes the regulated growth of a high-quality PVK film with less undesired defect. Hence, both the light-harvesting capability, the photoelectrons transport and extraction are improved, and the charge recombination is restrained, delivering an optimized power conversion efficiency (PCE) of 10.23 % with a high short-circuit current density of 7.88 mA cm−2 for the c -TiO 2 /Fe 2 O 3 @SnO 2 ETL based all-inorganic CsPbBr 3 PSCs. Moreover, under lasting erosion at 25 °C and 85 % RH for 30 days and light-soaking (AM 1.5G) for 480 h in air atmosphere, the unencapsulated-device shows superiorly persistent durability. [ABSTRACT FROM AUTHOR]

Perovskite nanocrystals (PeNCs) are known for their use in numerous optoelectronic applications. Surface ligands are critical for passivating surface defects to enhance the charge transport and photoluminescence quantum yields of the PeNCs. Herein, we investigated the dual functional abilities of bulky cyclic organic ammonium cations as surface-passivating agents and charge scavengers to overcome the lability and insulating nature of conventional long-chain type oleyl amine and oleic acid ligands. Here, red-emitting hybrid PeNCs of the composition CsxFA(1−x)PbBryI(3−y) are chosen as the standard (Std) sample, where cyclohexylammonium (CHA), phenylethylammonium (PEA) and (trifuluoromethyl)benzylamonium (TFB) cations were chosen as the bifunctional surface-passivating ligands. Photoluminescence decay dynamics showed that the chosen cyclic ligands could successfully eliminate the shallow defect-mediated decay process. Further, femtosecond transient absorption spectral (TAS) studies uncovered the rapidly decaying non-radiative pathways; i.e., charge extraction (trapping) by the surface ligands. The charge extraction rates of the bulky cyclic organic ammonium cations were shown to depend on their acid dissociation constant (pKa) values and actinic excitation energies. Excitation wavelength-dependent TAS studies indicate that the exciton trapping rate is slower than the carrier trapping rate of these surface ligands. [ABSTRACT FROM AUTHOR]

Cu2ZnSnS4 (CZTS) is a promising absorber material to produce thin film solar cells thanks to its high absorption coefficient, low cost and low toxicity. CdS is commonly used as a buffer layer for CZTS solar cells but, beyond its toxicity, it has a nonoptimal band alignment with CZTS. ZnxSn1−xO (ZTO), based on earth-abundant and nontoxic elements and with a large and tunable band gap, is a suitable alternative buffer layer. In this paper, the atomic layer deposition (ALD) of ZTO was employed by testing different compositions and thicknesses. ALD not only leads to very compact and homogenous ZTO layers (enabling tuning the stoichiometry of the ZTO so prepared) but also makes the i-ZnO layer (usually sandwiched between the buffer layer and the transparent contact) redundant and detrimental. Through SCAPS simulation and impedance measurements, the ZnSnO/AZO interface impact on the Cd-free kesterite solar cells' performances has been investigated, highlighting its leading role in achieving an effective charge extraction and the detrimental effect of the i-ZnO layer. With this approach, a solar cell based on an architecture simpler and more eco-friendly than the conventional one has been produced with comparable efficiencies. [ABSTRACT FROM AUTHOR]

Sb2(S, Se)3 solar cells have shown great promise due to the advantages of low cost, non-toxic and high stability. However, traditional devices commonly use noble metal as the back electrode, which not only increases device cost but also limits device stability. Herein, carbon materials are used to replace the noble metals in Sb2(S, Se)3 solar cells. In addition, to grow high-quality Sb2(S, Se)3 films, a two-step hydrothermal method was developed. The carbon-based Sb2(S, Se)3 solar cells based on the above film achieved a power conversion efficiency (PCE) of 2.76%. After inserting a stable P3HT layer at the Sb2(S, Se)3 film/carbon interface, hole extraction was enhanced and the PCE was promoted to 4.15%. This work brings out a promising route to produce emerging solar cells with cost-effective and stable materials. [ABSTRACT FROM AUTHOR]

Defect states at the surface and grain boundaries of perovskite films have been known to be major determinants impairing the optoelectrical properties of perovskite films and the stability of perovskite solar cells (PeSCs). Herein, an n‐type conjugated small‐molecule additive based on fused‐unit dithienothiophen[3,2‐b]‐pyrrolobenzothiadiazole‐core (JY16) is developed for efficient and stable PeSCs, where JY16 possesses the same backbone as the widely used Y6 but with long‐linear n‐hexadecyl side chains rather than branched side chains. Upon introducing JY16 into the perovskite films, the electron‐donating functional groups of JY16 passivate defect states in perovskite films and increase the grain size of perovskite films through Lewis acid–base interactions. Compared to Y6, JY16 exhibits superior charge mobility owing to its molecular packing ability and prevents decomposition of perovskite films under moisture conditions owing to their hydrophobic characteristics, improving the charge extraction ability and moisture stability of PeSCs. Consequently, the PeSC with JY16 shows a high power conversion efficiency of 21.35%, which is higher than those of the PeSC with Y6 (20.12%) and without any additive (18.12%), and outstanding moisture stability under 25% relative humidity, without encapsulation. The proposed organic semiconducting additive will prove to be crucial for achieving highly efficient and moisture stable PeSCs. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have witnessed an unprecedentedly rapid development, especially in terms of power conversion efficiency (PCE). However, the solution‐processed perovskite films inevitably possess numerous crystallographic defects (e.g., halide vacancies), which has been shown to incur non‐radiative charge recombination and ion migration, thus limiting the enhancement of the PCE and stability of PSCs. Here, a novel dual metal (i.e., divalent and monovalent metal ions) modification strategy is reported for simultaneously reducing the defects, immobilizing the halide anions, and preventing ion loss from perovskite during post‐annealing process. Accordingly, this strategy significantly reduces non‐radiative recombination, enhancing the PCE by ≈12% and mitigating the current density‐voltage (J–V) hysteresis effect in resultant devices compared to undoped counterparts. As a result, a champion PCE exceeding 22% and a high open‐circuit voltage (Voc) of 1.16 V is obtained for dual metal ions‐modified PSCs. The optimized devices also exhibit extended lifespan upon the dual metal treatment. The study provides a new defect engineering strategy toward more efficient and stable perovskite photovoltaics. [ABSTRACT FROM AUTHOR]

This study presents a facile approach of depositing 11-mercapto-undecanoic acid (11-MUA) on zinc oxide (ZnO) cathode interlayer in conventional STOPVs, resulting in ZnO/11-MUA/Ag electrode based STOPVs devices with superior optical and electrical correlation multifunctionality, including surface trap density that is 2 orders of magnitude lower than the counterparts based on ZnO/Ag, enhanced power conversion efficiency, significantly improvements in average visible transmittance and long-term thermal stability. [Display omitted] • 11-mercapto-undecanoic acid (11-MUA) is used to passivate the defects of ZnO. • 11-MUA induces the formation of high-quality ultrathin Ag electrode in semitransparent organic photovoltaics (STOPVs). • The surface trap density of STOPVs is obviously reduced by processing with 11-MUA. • 11-MUA simultaneously improves the efficiency and average visible transmittance of STOPVs. Charge recombination at the interface between top electrode and active layer is a substantial current loss pathway in semitransparent organic photovoltaics (STOPVs). Reducing interfacial traps is an effective strategy to mitigate interfacial recombination and promote charge extraction, and thereby improve the power conversion efficiencies (PCEs). Herein, a facile approach of depositing 11-mercapto-undecanoic acid (11-MUA) on zinc oxide (ZnO) cathode interlayer in conventional STOPVs is demonstrated. 11-MUA can form covalent interactions with both ZnO and silver (Ag) and thus can induce the formation of high-quality ultrathin Ag electrode. Compared with that deposited on bare ZnO, the Ag electrode on ZnO/11-MUA shows higher conductivity as well as higher optical transparency. The STOPVs based on ZnO/11-MUA/Ag exhibit 2 orders of magnitude lower surface trap density than the counterparts based on ZnO/Ag. Consequently, 11-MUA simultaneously improves the PCEs from 11.2% to 12.1% and average visible transmittance from 21.6% to 27.0% in the STOPVs. Furthermore, arising from the 11-MUA-modified interface, the thermal stability of STOPVs based on ZnO/11-MUA/Ag is also improved. [ABSTRACT FROM AUTHOR]

Abstract Defect states at the surface and grain boundaries of perovskite films have been known to be major determinants impairing the optoelectrical properties of perovskite films and the stability of perovskite solar cells (PeSCs). Herein, an n‐type conjugated small‐molecule additive based on fused‐unit dithienothiophen[3,2‐b]‐pyrrolobenzothiadiazole‐core (JY16) is developed for efficient and stable PeSCs, where JY16 possesses the same backbone as the widely used Y6 but with long‐linear n‐hexadecyl side chains rather than branched side chains. Upon introducing JY16 into the perovskite films, the electron‐donating functional groups of JY16 passivate defect states in perovskite films and increase the grain size of perovskite films through Lewis acid–base interactions. Compared to Y6, JY16 exhibits superior charge mobility owing to its molecular packing ability and prevents decomposition of perovskite films under moisture conditions owing to their hydrophobic characteristics, improving the charge extraction ability and moisture stability of PeSCs. Consequently, the PeSC with JY16 shows a high power conversion efficiency of 21.35%, which is higher than those of the PeSC with Y6 (20.12%) and without any additive (18.12%), and outstanding moisture stability under 25% relative humidity, without encapsulation. The proposed organic semiconducting additive will prove to be crucial for achieving highly efficient and moisture stable PeSCs.

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There is an urgent need to use green non-halogenated solvents to prepare polymer solar cells (PSCs) for industrialization. It is time-consuming but necessary to find a suitable non-halogenated solvent/additive combination for a given donor:acceptor materials system. In this research, we report a non-halogenated binary solvent system toluene/diphenyl ether (DPE) for the PBDTT-DTffBT:PC71BM and PM6:Y6 blending systems that exhibit comparable power conversion efficiency (PCE) to that of devices prepared with halogenated solvents. The nanoscale morphology indicates that blending film processed solely with toluene has poor phase segregation and a rough surface, which hinders charge separation and interfacial contact. Besides, the total absorption spectra revealed significant light-trapping losses in the toluene-processed solar cells, resulting in low photocurrent generation. DPE incorporation addresses these issues and significantly improves the short-circuit current density and fill factor. Moreover, non-halogen solvent-processed devices exhibit high hole mobility and low transporting impedance properties. The present study enriches the families of eco-friendly, high-efficiency PSCs fabricated using non-halogenated solvents. [ABSTRACT FROM AUTHOR]

Perovskite/organic tandem solar cells (POTSCs) have garnered significant attention due to their potential for achieving high photovoltaic (PV) performance. However, the reported power conversion efficiencies (PCEs) and fill factors (FFs) are still subpar due to the challenges associated with charge extraction in the organic bulk-heterojunction (BHJ) and significant energy losses in the interconnecting layers (ICLs). Here, a quaternary organic BHJ blend is developed to enhance the charge extraction in the organic subcell, contributing to an increased FF of ≥78% under 1 sun illumination and even more under lower illumination intensities. Meanwhile, energy losses in the ICLs are reduced via the incorporation of a self-assembly monolayer (SAM), (4-(3,6-Dimethyl-9H-carbazol-9-yl)butyl)phosphonic acid (Me-4PACz), in organic BHJ to form a MoO x /SAM interface and the thorough control of the MoO x thickness to suppress parasitic absorption. The resultant POTSCs achieve a remarkable PCE of 25.56% (certified: 24.65%), with a record FF of 83.62%, which is among the highest PCEs of POTSCs and the highest FF of all types of perovskite-based tandem solar cells (TSCs) till now. This work proves the optimization of charge extraction and ICLs are effective strategies to promote the performance of POTSCs to surpass other solution-processed perovskite-based TSCs in the near future., (© 2024 Wiley‐VCH GmbH.)

Since the advent of formamidinium (FA)-based perovskite photovoltaics (PVs), significant performance enhancements have been achieved. However, a critical challenge persists: the propensity for void formation in the perovskite film at the buried perovskite-interlayer interface has a deleterious effect on device performance. With most emerging perovskite PVs adopting the p-i-n architecture, the specific challenge lies at the perovskite-hole transport layer (HTL) interface, with previous strategies to overcome this limitation being limited to specific perovskite-HTL combinations; thus, the lack of universal approaches represents a bottleneck. Here, we present a novel strategy that overcomes the formation of such voids (microstructural defects) through a film treatment with methylammonium chloride (MACl). Specifically, our work introduces MACl via a sequential deposition method, having a profound impact on the microstructural defect density at the critical buried interface. Our technique is independent of both the HTL and the perovskite film thickness, highlighting the universal nature of this approach. By employing device photoluminescence measurements and conductive atomic force microscopy, we reveal that when present, such voids impede charge extraction, thereby diminishing device short-circuit current. Through comprehensive steady-state and transient photoluminescence spectroscopy analysis, we demonstrate that by implementing our MACl treatment to remedy these voids, devices with reduced defect states, suppressed nonradiative recombination, and extended carrier lifetimes of up to 2.3 μs can be prepared. Furthermore, our novel treatment reduces the stringent constraints around antisolvent choice and dripping time, significantly extending the processing window for the perovskite absorber layer and offering significantly greater flexibility for device fabrication.

CsPbI 3 perovskite quantum dot (PQD) shows high potential for next-generation photovoltaics due to their tunable surface chemistry, good solution-processability and unique photophysical properties. However, the remained long-chain ligand attached to the PQD surface significantly impedes the charge carrier transport within the PQD solids, thereby predominantly influencing the charge extraction of PQD solar cells (PQDSCs). Herein, a ligand-induced energy level modulation is reported for band engineering of PQD solids to improve the charge extraction of PQDSCs. Detailed theoretical calculations and systemic experimental studies are performed to comprehensively understand the photophysical properties of the PQD solids dominated by the surface ligands of PQDs. The results reveal that 4-nitrobenzenethiol and 4-methoxybenzenethiol molecules with different dipole moments can firmly anchor to the PQD surface through the thiol group to modulate the energy levels of PQDs, and a gradient band structure within the PQD solid is subsequently realized. Consequently, the band-engineered PQDSC delivers an efficiency of up to 16.44%, which is one of the highest efficiencies of CsPbI 3 PQDSCs. This work provides a feasible avenue for the band engineering of PQD solids by tuning the surface chemistry of PQDs for high-performing solar cells or other optoelectronic devices., (© 2024 Wiley‐VCH GmbH.)

The backreaction in dye-sensitized solar cells (DSSCs) was long ago recognized as one of the main causes of decreasing energy conversion efficiency. Hence, many different approaches have been attempted to reduce the backreaction. In the present work, we use nitrogen additives in the electrolyte to reduce the backreaction with TiO2 and I3−. Intensity-modulated photocurrent/photovoltage (IMPS/IMVS) and charge extraction (CE) techniques are used to obtain information on the dynamics of charge carriers in DSSCs assembled with and without nitrogen additives. The passivation process occurring on the nanoparticles, which is promoted by the additives, prevents recombination but does not change the electron transport time. Therefore, the description of transport and electron recombination kinetics in DSSCs is well established in this work with the emerging IMPS, IMVS, and CE techniques.

In perovskite solar cells (PSCs), defective perovskite grain boundaries (GBs) and/or surface due to photo‐excitation and the resulted suboptimal carrier dynamics at the perovskite/charge transport layer, have largely limited further performance enhancement and aggravated the PSCs instability. Fundamentally preventing the formation of these trap‐states through a simple and efficient approach is thus critical to the enhancement of both device performance and stability. Herein, a novel semiconductive silicon naphthalocyanine derivative (Cl‐SiNcTI) to reduce the deep level trap states at the GBs and the surface of perovskite film is successfully employed via a newly proposed photon‐relaxation mechanism. The resulting benign p‐type surface polarity and suppressed non‐radiation recombination lead to improved charge transport in bulk perovskite and at the perovskite/spiro‐OMeTAD interface. With a synergistic contribution of the Cl‐SiNcTI and 2‐(2‐Fluorophenyl)ethylamine iodide (oFPEAI), a 24.30% efficiency is achieved in a single cell with excellent operational stability. Moreover, under steady‐state light illumination, 93% power output compared to its initial state can still be maintained after 250 h of continuous operation. [ABSTRACT FROM AUTHOR]

Herein, a strong short‐circuit current density (JSC) loss is observed when using phenetylammonium iodide (PEAI) as n‐side passivation in p–i–n perovskite solar cells. Comparing experiments with drift–diffusion simulations, different hypotheses for the origin of the JSC loss are presented and evaluated. Whereas the optical properties of the investigated cell stack remain unchanged, the internal quantum efficiency of the PEAI‐based devices decreases drastically. Strong bulk doping and interface traps are ruled out as the origin of the charge extraction limitation. High‐spatial resolution photoluminescence (PL) spectroscopy directly images the inhomogeneity of the PEAI‐based quasi‐2D perovskite wide‐bandgap interlayer, which is found to be crucial for the observed JSC loss. A 2D drift–diffusion model implemented with mobile ions and an inhomogeneous electron transport layer reproduces the experimental behavior accurately. The ionic space charge distribution under short circuit reduces the effective charge‐carrier diffusion length, hindering charge transport toward those domains in the perovskite–electron transport layer interface where electrons can be extracted efficiently. A longer charge‐carrier lifetime reduces the JSC loss, highlighting the importance of suppressed non‐radiative bulk recombination, not only for achieving high open‐circuit voltages, but also for efficient charge extraction. [ABSTRACT FROM AUTHOR]

The development of high-efficiency and stable perovskite (PVK) solar cells (PSCs) still faces the challenge of non-ideal interfaces between PVK and charge transport layers. Herein, the hexafluoroisopropanol (HFIP) modified two-dimensional Ti 3 C 2 T x MXene is custom-made (MX-HFIP) and employed as the interlayer between the PVK and hole transport layer (HTL) interface by forming hydrogen bonds. The MX-HFIP serves to reinforce the interface contact and remodel the surface of PVK, leading to a high-quality PVK film with a significantly reduced defect density, suppressed nonradiative recombination, and inhibited invasion of water and oxygen. Moreover, the synergistic effect of MXene and HFIP results in an enhanced interfacial dipole effect and an optimized energy-level alignment, thereby increasing the driving force for charge extraction and transport at the PVK/HTL interface. Therefore, the MX-HFIP treated PSC achieves a substantially-enhanced power conversion efficiency (PCE) of 22.33 %, as compared to 20.05 % of the untreated device. Besides, the MX-HFIP treated PSC delivers significantly enhanced stabilities, with 88 % of its initial PCE after 1656 h of storage at 25 °C under 30 %⁓40 % relative humidity. These findings demonstrate the advancement using fluorine-rich molecule modified MXene to improve interfacial properties for enhancing performances and stabilities of optoelectronic devices. [Display omitted] • MX-HFIP is employed to modify the PVK/HTL interface. • MX-HFIP reinforces the interface contact by forming hydrogen bonds. • PVK surface is remodeled and film quality is improved. • Interfacial dipole effect is enhanced to promote charge extraction and transport. • Performances and stabilities of PSCs are substantially enhanced. [ABSTRACT FROM AUTHOR]

Perovskite nanocrystals (PeNCs) are known for their use in numerous optoelectronic applications. Surface ligands are critical for passivating surface defects to enhance the charge transport and photoluminescence quantum yields of the PeNCs. Herein, we investigated the dual functional abilities of bulky cyclic organic ammonium cations as surface-passivating agents and charge scavengers to overcome the lability and insulating nature of conventional long-chain type oleyl amine and oleic acid ligands. Here, red-emitting hybrid PeNCs of the composition CsxFA(1−x)PbBryI(3−y) are chosen as the standard (Std) sample, where cyclohexylammonium (CHA), phenylethylammonium (PEA) and (trifuluoromethyl)benzylamonium (TFB) cations were chosen as the bifunctional surface-passivating ligands. Photoluminescence decay dynamics showed that the chosen cyclic ligands could successfully eliminate the shallow defect-mediated decay process. Further, femtosecond transient absorption spectral (TAS) studies uncovered the rapidly decaying non-radiative pathways; i.e., charge extraction (trapping) by the surface ligands. The charge extraction rates of the bulky cyclic organic ammonium cations were shown to depend on their acid dissociation constant (pKa) values and actinic excitation energies. Excitation wavelength-dependent TAS studies indicate that the exciton trapping rate is slower than the carrier trapping rate of these surface ligands.

Cu2ZnSnS4 (CZTS) is a promising absorber material to produce thin film solar cells thanks to its high absorption coefficient, low cost and low toxicity. CdS is commonly used as a buffer layer for CZTS solar cells but, beyond its toxicity, it has a nonoptimal band alignment with CZTS. ZnxSn1−xO (ZTO), based on earth-abundant and nontoxic elements and with a large and tunable band gap, is a suitable alternative buffer layer. In this paper, the atomic layer deposition (ALD) of ZTO was employed by testing different compositions and thicknesses. ALD not only leads to very compact and homogenous ZTO layers (enabling tuning the stoichiometry of the ZTO so prepared) but also makes the i-ZnO layer (usually sandwiched between the buffer layer and the transparent contact) redundant and detrimental. Through SCAPS simulation and impedance measurements, the ZnSnO/AZO interface impact on the Cd-free kesterite solar cells’ performances has been investigated, highlighting its leading role in achieving an effective charge extraction and the detrimental effect of the i-ZnO layer. With this approach, a solar cell based on an architecture simpler and more eco-friendly than the conventional one has been produced with comparable efficiencies.

Sb2(S, Se)3 solar cells have shown great promise due to the advantages of low cost, non-toxic and high stability. However, traditional devices commonly use noble metal as the back electrode, which not only increases device cost but also limits device stability. Herein, carbon materials are used to replace the noble metals in Sb2(S, Se)3 solar cells. In addition, to grow high-quality Sb2(S, Se)3 films, a two-step hydrothermal method was developed. The carbon-based Sb2(S, Se)3 solar cells based on the above film achieved a power conversion efficiency (PCE) of 2.76%. After inserting a stable P3HT layer at the Sb2(S, Se)3 film/carbon interface, hole extraction was enhanced and the PCE was promoted to 4.15%. This work brings out a promising route to produce emerging solar cells with cost-effective and stable materials.

Interface engineering is an effectively method for high‐performance perovskite solar cells. Here, for the first time, we implemented a universal bio‐energy carrier‐adenosine triphosphate (ATP), in the form of adenosine triphosphate disodium (ATPS) on a conjugated polyelectrolytes poly [3‐(4‐carboxybutyl)thiophene‐2,5‐diyl] sodium (P3CTS) hole transport layer (HTL) as a facile interfacial modification for efficient inverted perovskite solar cells. ATPS was explored to hold the capability to bridge the P3CTS HTL and the photo‐active perovskite, where the phosphate group of ATPS could passivate the uncoordinated Pb of perovskite via chelation while the adenine group could interact with the carboxyl group of P3CTS. An optimized and moderate band alignment was found in ATPS modified P3CTS HTL with subtle reduced valence band maximum (VBM). Meanwhile, the upper methylammonium lead halide (MAPbI3) perovskite layer on ATPS modified P3CTS HTL showed a superior film quality with larger crystal size and less surface defects. Accordingly, bimolecular recombination was found to be dominant associated to the reduced charge carrier recombination in the ATPS device while the charge extraction across HTL/perovskite interface was also apparently facilitated. As a result, the ATPS modified photovoltaic device exhibited an open current voltage (Voc) of around 1.10 V and power conversion efficiency (PCE) of 20.15%. Furthermore, the shelf stability of the ATPS device is much superior with almost no decay after 3 months (>2000 h), while only 75% of the original PCE maintained for the control. The work provides a facile interfacial strategy utilizing biomaterials towards efficient and stable perovskite solar cells. [ABSTRACT FROM AUTHOR]

Interfacial engineering is the key to high‐performance perovskite solar cells (PSCs). While a wide range of fullerene interlayers are investigated for Pb‐based counterparts with a bandgap of >1.5 eV, the role of fullerene interlayers is barely investigated in Sn‐Pb mixed narrow‐bandgap (NBG) PSCs. In this work, two novel solution‐processed fullerene derivatives are investigated, namely indene‐C60‐propionic acid butyl ester and indene‐C60‐propionic acid hexyl ester (IPH), as the interlayers in NBG PSCs. It is found that the devices with IPH‐interlayer show the highest performance with a remarkable short‐circuit current density of 30.7 mA cm−2 and a low deficit in open‐circuit voltage. The reduction in voltage deficit down to 0.43 V is attributed to reduced non‐radiative recombination that the authors attribute to two aspects: 1) a higher conduction band offset of ≈0.2 eV (>0 eV) that hampers charge‐carrier‐back‐transfer recombination; 2) a decrease in trap density at the perovskite/interlayer/C60 interfaces that results in reduced trap‐assisted recombination. In addition, incorporating the IPH interlayer enhances charge extraction within the devices that results in considerable enhancement in short‐circuit current density. Using a NBG device with an IPH interlayer, a respectable power conversion efficiency of 24.8% is demonstrated in a four‐terminal all‐perovskite tandem solar cell. [ABSTRACT FROM AUTHOR]

An excellent organolead halide perovskite film is important for the good performance of perovskite solar cells (PSCs). However, defects in perovskite crystals can affect the photovoltaic properties and stability of solar cells. To solve this problem, this study incorporated a complex of CdS and Cd(SCN2H4)2Cl2 into the CH3NH3PbI3 active layer. The effects of different doping concentrations of CdS and Cd(SCN2H4)2Cl2 on the performance and stability of PSCs were analyzed. Results showed that doping appropriate incorporation concentrations of CdS and Cd(SCN2H4)2Cl2 in CH3NH3PbI3 can improve the performance of the prepared solar cells. In specific, CdS and Cd(SCN2H4)2Cl2 can effectively passivate the defects in perovskite crystals, thereby suppressing the charge recombination in PSCs and promoting the charge extraction at the TiO2/perovskite interface. Due to the reduction of perovskite crystal defects and the enhancement of compactness of the CdS:Cd(SCN2H4)2Cl2:CH3NH3PbI3 composite film, the stability of PSCs is significantly improved. [ABSTRACT FROM AUTHOR]

The heterointerface between the contacted organic and inorganic semiconductors critically affects the charge extraction, hence overall performance of organic optoelectronics, especially for organic solar cells (OSCs). Herein, we develop an effective interfacial strategy that simultaneously boosts the chemical, electric, and electronic properties of the organic–inorganic heterointerface of the derived OSCs, through implanting conjugated molecules as self‐assemble monolayers (SAMs) to metal oxide nanoparticles (MO NPs). As results, SAM passivated zinc oxide nanoparticles (ZnO NPs) as electron transport layers (ETLs) not only enable the best performed OSCs containing MO ETLs, but also exhibit the most desirable thickness insensitive features (up to 300 nm). In addition, SAM‐ZnO ETLs help also substantially improving the photostability of the derived OSCs. Overall, this work can be beneficial to the further development of high‐performance and cost‐effective OSCs. [ABSTRACT FROM AUTHOR]

Abstract The heterointerface between the contacted organic and inorganic semiconductors critically affects the charge extraction, hence overall performance of organic optoelectronics, especially for organic solar cells (OSCs). Herein, we develop an effective interfacial strategy that simultaneously boosts the chemical, electric, and electronic properties of the organic–inorganic heterointerface of the derived OSCs, through implanting conjugated molecules as self‐assemble monolayers (SAMs) to metal oxide nanoparticles (MO NPs). As results, SAM passivated zinc oxide nanoparticles (ZnO NPs) as electron transport layers (ETLs) not only enable the best performed OSCs containing MO ETLs, but also exhibit the most desirable thickness insensitive features (up to 300 nm). In addition, SAM‐ZnO ETLs help also substantially improving the photostability of the derived OSCs. Overall, this work can be beneficial to the further development of high‐performance and cost‐effective OSCs.

Abstract Non‐fullerene acceptors are currently a hot research area in the development of organic solar cells (OSCs). At present, the‐state‐of‐the‐art power conversion efficiency (PCE) of non‐fullerene organic solar cells (NF‐OSCs) with single and multiple‐junction has surpassed 18% and 19%, respectively. The cathode interlayer (CIL) plays a significant role in the improvement of PCE and the stability of OSCs. Recently, a large number of CIL materials have been employed in OSCs. This review summarizes the recent progress of CIL materials and systematically describes their impact on the device efficiency and stability in single‐junction NF‐OSCs. Firstly, the functions, key requirements, and distinctive features of CILs when used in NF‐OSCs are summarized. Afterward, some big families of materials including metal oxides, metal salts/complexes, small molecules, polymers, composites/hybrids are presented as CIL for NF‐OSCs. Finally, the scale‐up techniques, conclusion, and future challenges regarding CIL in NF‐OSCs are elucidated.

Ionic carbon nitrides based on poly(heptazine imides) (PHI) represent a vigorously studied class of materials with possible applications in photocatalysis and energy storage. Herein, for the first time, the photogenerated charge dynamics in highly stable and binder‐free PHI photoanodes using in operando transient photocurrents and spectroelectrochemical photoinduced absorption measurements is studied. It is discovered that light‐induced accumulation of long‐lived trapped electrons within the PHI film leads to effective photodoping of the PHI film, resulting in a significant improvement of photocurrent response due to more efficient electron transport. While photodoping is previously reported for various semiconductors, it has not been shown before for carbon nitride materials. Furthermore, it is found that the extraction kinetics of untrapped electrons are remarkably fast in these PHI photoanodes, with electron extraction times (ms) comparable to those measured for commonly employed metal oxide semiconductors. These results shed light on the excellent performance of PHI photoanodes in alcohol photoreforming, including very negative photocurrent onset, outstanding fill factor, and the possibility to operate under zero‐bias conditions. More generally, the here reported photodoping effect and fast electron extraction in PHI photoanodes establish a strong rationale for the use of PHI films in various applications, such as bias‐free photoelectrochemistry or photobatteries. [ABSTRACT FROM AUTHOR]

SnO 2 is recognized as an excellent electron transport layer. However, it does not possess the optimal morphology required by perovskite photovoltaic devices, and the conduction band of SnO 2 cannot match well with perovskite conduction bands. In the present study, we introduced graphene quantum dots (GQDs) into SnO 2. The results show that the introduction of graphene quantum dots effectively improved the morphology of the SnO 2 film, reduced the roughness of the surface, and increased the ohmic contact between the SnO 2 and perovskite layer. In addition, the conductivity of the SnO 2 film was improved, thereby facilitating the transfer of electrons. The optimized SnO 2 : GQDs layer reduced the density of defect state, suppressed the pinholes appearance to a certain extent, and facilitated the extraction of electrons, thereby ultimately improving the FF, and increasing the efficiency of the perovskite photovoltaic device. [ABSTRACT FROM AUTHOR]

Simplified perovskite solar cells (PSCs) were fabricated with the perovskite layer sandwiched and encapsulated between carbon‐based electron transport layer (ETL) and counter electrode (CE) by a fully blade‐coated process. A self‐assembled monolayer of amphiphilic silane (AS) molecules on transparent conducting oxide (TCO) substrate appeals to the fullerene ETL deposition and preserves its integrity against the solvent damage. The AS serves as a "molecular glue" to strengthen the adhesion toughness at the TCO/ETL interface via robust chemical interaction and bonding, facilitating the interfacial charge extraction, increasing PCEs by 77 % and reducing hysteresis. A PCE of 18.64 % was achieved for the fully printed devices, one of the highest reported for carbon‐based PSCs. AS‐assisted interfacial linkage and carbon‐material‐assisted self‐encapsulation enhance the stability of the PSCs, which did not experience performance degradation when stored at ambient conditions for over 3000 h. [ABSTRACT FROM AUTHOR]

A fullerene-based molecular passivator, namely C 60 - t Bu-I, has been firstly developed as interfacial layers between a perovskite and electron transport layers in planar invert perovskite solar cells (PVSCs), which exhibit high efficiency up to 17.75% with negligible hysteresis and good device stability. [Display omitted] • A conducting fullerene-based surface passivator is designed and synthesized. • Positively and negatively charged surface defects could be simultaneously passivated. • The remarkably enhanced PCE value and stability could be obtained. Interfacial defects result in a limitation to the development of highly efficient and stable perovskite solar cells. The passivation of these defects by adopting various interfacial defects passivation agents is a common method for boosting device performance. However, most existing interfacial defects passivation agents form poorly conductive aggregates at the perovskite interface with the electron transport layer (ETL), hindering the transport of charge carriers. In addition, the electron mobility of passivation agents is an important factor that affects the electron communication between the adjacent layers. Herein, a fullerene-based molecular passivator, [60]fullerene-4-(1-(4-(tert -butyl)phenyl)pyrrolidin-2-yl)benzenaminium (C 60 - t Bu-I), is designed and synthesized. This novel n -doping fullerene ammonium iodide is developed as an interfacial modification agent to accelerate charge transport from the perovskite active layer into the ETL while hindering the nonradiative charge carrier recombination. Hence, compared with the control devices (15.66%), C 60 - t Bu-I-modified device presents a higher efficiency of 17.75%. More importantly, the tert -butyl group dramatically enhances the resistance of perovskite films to water molecular. As a result, C 60 - t Bu-I-modified devices exhibit excellent long-term stability, remaining at more than 87% of the initial power conversion efficiency value after storage for 500 h. [ABSTRACT FROM AUTHOR]