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Highlights The soft 2D material reduces the coupling strength between carriers and longitudinal optical phonons, releasing the mechanical stress of lattice vibration. The power conversion efficiency of rigid devices and flexible devices reaches 25.5% and 23.4%, respectively.

Highlights: The soft 2D material reduces the coupling strength between carriers and longitudinal optical phonons, releasing the mechanical stress of lattice vibration. The power conversion efficiency of rigid devices and flexible devices reaches 25.5% and 23.4%, respectively. This study presents experimental evidence of the dependence of non-radiative recombination processes on the electron–phonon coupling of perovskite in perovskite solar cells (PSCs). Via A-site cation engineering, a weaker electron–phonon coupling in perovskite has been achieved by introducing the structurally soft cyclohexane methylamine (CMA+) cation, which could serve as a damper to alleviate the mechanical stress caused by lattice oscillations, compared to the rigid phenethyl methylamine (PEA+) analog. It demonstrates a significantly lower non-radiative recombination rate, even though the two types of bulky cations have similar chemical passivation effects on perovskite, which might be explained by the suppressed carrier capture process and improved lattice geometry relaxation. The resulting PSCs achieve an exceptional power conversion efficiency (PCE) of 25.5% with a record-high open-circuit voltage (VOC) of 1.20 V for narrow bandgap perovskite (FAPbI3). The established correlations between electron–phonon coupling and non-radiative decay provide design and screening criteria for more effective passivators for highly efficient PSCs approaching the Shockley–Queisser limit. [ABSTRACT FROM AUTHOR]

In this study, micro-light emitting diodes array (μLEDs) with dimensions of 5 μm and 15 μm chip size were fabricated using Neutral Beam Etching (NBE) processes. Size-dependent issues of μLEDs processed by traditional inductively coupled plasma-reactive ion etching (ICPRIE) were alleviated by NBE technology, which exhibited lower equivalent resistance, turn-on voltage, and Ideality factor as compared with those of μLEDs by ICPRIE. Additionally, higher light output power of μLEDs processed by NBE with both 5 μm and 15 μm resulted in higher EQE 7.6 % and 7.7 % than those of μLEDs processed by ICPRIE. Furthermore, the size effect led to a decrease in EQEmax values of the ICPRIE sample by 0.4 %, but only a 0.1 % decay in NBE. Overall, samples fabricated by the NBE process exhibited superior optoelectronic characteristics. Finally, non-radiative recombination behaviors on the mesa sidewall were verified by cathodoluminescence analysis, showing significant decay in ICPRIE samples but not in NBE samples. These results demonstrated the potential of the NBE process for fabricating small chip sizes blue-light μLEDs required for high-brightness, high-efficiency, and high-resolution μLED displays.

GaN-based micro-size light-emitting diodes (µLEDs) have a variety of attractive and distinctive advantages for display, visible-light communication (VLC), and other novel applications. The smaller size of LEDs affords them the benefits of enhanced current expansion, fewer self-heating effects, and higher current density bearing capacity. Low external quantum efficiency (EQE) resulting from non-radiative recombination and quantum confined stark effect (QCSE) is a serious barrier for application of µLEDs. In this work, the reasons for the poor EQE of µLEDs are reviewed, as are the optimization techniques for improving the EQE of µLEDs. [ABSTRACT FROM AUTHOR]

Generally, the inductively coupled plasma-reactive ion etching (ICP-RIE) mesa technology was used to remove p-GaN/MQWs and expose n-GaN for electrical contact in a fabricated micro light-emitting diode (μLED). In this process, the exposed sidewalls were significantly damaged which result in small-sized μLED presenting a strong size-dependent influence. Lower emission intensity was observed in the μLED chip, which can be attributed to the effect of sidewall defect during etch processing. To reduce the non-radiative recombination, the ion implantation using an As+ source to substitute the ICP-RIE mesa process was introduced in this study. The ion implantation technology was used to isolate each chip to achieve the mesa process in the μLED fabrication. Finally, the As+ implant energy was optimized at 40 keV, which exhibited excellent current–voltage characteristics, including low forward voltage (3.2 V @1 mA) and low leakage current (10–9 A@− 5 V) of InGaN blue μLEDs. The gradual multi-energy implantation process from 10 to 40 keV can further improve the electrical properties (3.1 V @1 mA) of μLEDs, and the leakage current was also maintained at 10–9 A@− 5 V. [ABSTRACT FROM AUTHOR]

Interface properties between charge transport and perovskite light-absorbing layers have a significant impact on the power conversion efficiency (PCE) of perovskite solar cells (PSCs). Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is a polyelectrolyte composite that is widely used as a hole transport layer (HTL) to facilitate hole transport from a perovskite layer to an anode. However, PEDOT:PSS must be modified using a functional additive because PSCs with a pristine PEDOT:PSS HTL do not exhibit a high PCE. Herein, we demonstrate an increase in the PCE of PSCs with a polyethylene glycol hexadecyl ether (Brij C10)-mixed PEDOT:PSS HTL. Photoelectron spectroscopy results show that the Brij C10 content becomes significantly high in the HTL surface composition with an increase in the Brij C10 concentration (0–5 wt%). The enhanced PSC performance, e.g., a PCE increase from 8.05 to 11.40%, is attributed to the reduction in non-radiative recombination at the interface between PEDOT:PSS and perovskite by the insulating Brij C10. These results indicate that the suppression of interface recombination is essential for attaining a high PCE for PSCs. [ABSTRACT FROM AUTHOR]

Abstract Inverted perovskite solar cells (inverted‐PSCs) have exhibited advantages of longer stability, less hysteresis, and lower fabrication temperature when compared to their regular counterparts, which are important for industry commercialization. Because of the great efforts that have been conducted in the past several years, the obtained efficiency of inverted‐PSCs has almost caught up with that of the regular ones, 25.0% versus 25.7%. In this perspective, the recent studies on the design of high‐performance inverted‐PSCs based on diverse hole transport materials, as well as device fabrication and characterization are first reviewed. After that, the authors moved on to the interface and additive engineering that were exploited to suppress the nonradiative recombination. Finally, the challenges and possible research pathways for facilitating the industrialization of inverted‐PSCs were envisaged.

The influence of P3HT:PCBM ratio on thermal and transport properties of solar cells were determined by photothermal beam deflection spectrometry, which is advantageous tool for non-destructively study of bulk heterojunction layers of organic solar cells. P3HT:PCBM layers of different P3HT:PCBM ratios were deposited on top of PEDOT:PSS/ITO layers which were included in organic bulk-heterojunction solar cells. The thermal diffusivity, energy gap and charge carrier lifetime were measured at different illumination conditions and with a different P3HT:PCBM ratios. As expected, it was found that the energy band gap depends on the P3HT:PCBM ratio. Thermal diffusivity is decreasing, while charge carrier lifetime is increasing with PCBM concentration. Energy band gap was found to be independent on illumination intensity, while thermal diffusivity was increasing and carrier lifetime was decreasing with illumination intensity. The carrier lifetime exhibits qualitatively similar dependence on the PCBM concentration when compared to the open-circuit voltage of operating solar cells under AM1.5 illumination. BDS and standard I-V measurement yielded comparable results arguing that the former is suitable for characterization of organic solar cells. [ABSTRACT FROM AUTHOR]

In order to achieve the applications of the ZnO nanorod arrays in the novel nanostructured solar cells, it is necessary to tailor and control the nanorods' morphological, optical and electrical properties. The ZnO nanorods arrays were fabricated by electrodeposition. The physical properties such as the diameter, density, distance, optical band gap energy, near band emission and Stokes shift can be adjusted by the use of In(NO3)3 and NH4NO3.The characterizations such as scanning electron microscopy, X-ray diffraction spectrometer and photoluminescence were used to measure the samples' morphology, crystal property, transmission and reflection and photoluminescence properties. According to the measurement results, the ZnO nanorod arrays' density is reduced to 5.9×109 cm-2 and the distance between nanorods is enlarged to 108 nm by using NH4NO3. The nanorods' diameter is decreased to 22 nm. The use of In(NO3)3 leads to the blue shift of the ZnO nanorods' optical band gap energy by 100 meV. The optical band gap energy is further tailored between 3.41 eV and 3.55 eV by using NH4NO3. The ZnO nanorods' Stokes shift can be decreased to 19 meV by using NH4NO3, resulting in the effective suppression of the non-radiative recombination.

The role of defects in photocatalysis is rarely investigated more intuitively from the perspective of defect ionization energy (DIE), although it is the most important parameter for evaluating the depth of defect traps. Here, the crystalline poly(heptazine imide) (PHI) is adopted as an illustrative example to optimize the DIE and charge separation by regulating the carbon doping contents, ultimately activating the near-infrared photocatalytic activity. Shallow defect traps induced by doping (DIE < 25 meV) facilitate charge separation by releasing shallowly trapped carriers. In contrast, deep defect traps (DIE > 25 meV) act as non-radiative recombination centers, causing carrier quenching. More importantly, the non-radiative recombination rate in PHI is 1–2 orders of magnitude faster than the radiative recombination rate, so suppressing non-radiative recombination is more important for improving charge separation efficiency. Our work elucidates the role of defects in photocatalysis more intuitively from the perspective of DIE, and establishes a discernible relationship between DIE and photocatalytic activity. [Display omitted] • A carbon doping strategy with one stone and two birds has been proposed. • Elucidating the role of defects in photocatalysis more intuitively from the perspective of DIE. • High NIR photocatalytic activity. [ABSTRACT FROM AUTHOR]

The photovoltaic performance of C/O/S-doped hexagonal boron nitride (h-BN) quantum dots (QDs) is studied using density functional theory. Doping leads to occupied or unoccupied midgap states in h-BN QDs, resulting in a redshift in their absorption spectra. C-doping provides better charge transfer capability than S/O-doping. In addition, C-doping reduces the open-circuit voltage, light collection efficiency, fill factor, and driving forces of electron injection and reduction of h-BN QD. However, the fast non-radiative recombination deteriorates the energy conversion of C-doped h-BN QDs. The current study provides evidence for the rational design of photocatalytic devices based on h-BN QDs.

GaN-based micro-size light-emitting diodes (µLEDs) have a variety of attractive and distinctive advantages for display, visible-light communication (VLC), and other novel applications. The smaller size of LEDs affords them the benefits of enhanced current expansion, fewer self-heating effects, and higher current density bearing capacity. Low external quantum efficiency (EQE) resulting from non-radiative recombination and quantum confined stark effect (QCSE) is a serious barrier for application of µLEDs. In this work, the reasons for the poor EQE of µLEDs are reviewed, as are the optimization techniques for improving the EQE of µLEDs.

Interface properties between charge transport and perovskite light-absorbing layers have a significant impact on the power conversion efficiency (PCE) of perovskite solar cells (PSCs). Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is a polyelectrolyte composite that is widely used as a hole transport layer (HTL) to facilitate hole transport from a perovskite layer to an anode. However, PEDOT:PSS must be modified using a functional additive because PSCs with a pristine PEDOT:PSS HTL do not exhibit a high PCE. Herein, we demonstrate an increase in the PCE of PSCs with a polyethylene glycol hexadecyl ether (Brij C10)-mixed PEDOT:PSS HTL. Photoelectron spectroscopy results show that the Brij C10 content becomes significantly high in the HTL surface composition with an increase in the Brij C10 concentration (0–5 wt%). The enhanced PSC performance, e.g., a PCE increase from 8.05 to 11.40%, is attributed to the reduction in non-radiative recombination at the interface between PEDOT:PSS and perovskite by the insulating Brij C10. These results indicate that the suppression of interface recombination is essential for attaining a high PCE for PSCs.

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office 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.)

The influence of P3HT:PCBM ratio on thermal and transport properties of solar cells were determined by photothermal beam deflection spectrometry, which is advantageous tool for non-destructively study of bulk heterojunction layers of organic solar cells. P3HT:PCBM layers of different P3HT:PCBM ratios were deposited on top of PEDOT:PSS/ITO layers which were included in organic bulk-heterojunction solar cells. The thermal diffusivity, energy gap and charge carrier lifetime were measured at different illumination conditions and with a different P3HT:PCBM ratios. As expected, it was found that the energy band gap depends on the P3HT:PCBM ratio. Thermal diffusivity is decreasing, while charge carrier lifetime is increasing with PCBM concentration. Energy band gap was found to be independent on illumination intensity, while thermal diffusivity was increasing and carrier lifetime was decreasing with illumination intensity. The carrier lifetime exhibits qualitatively similar dependence on the PCBM concentration when compared to the open-circuit voltage of operating solar cells under AM1.5 illumination. BDS and standard I-V measurement yielded comparable results arguing that the former is suitable for characterization of organic solar cells.

The possibility to manufacture perovskite solar cells (PSCs) at low temperatures paves the way to flexible and lightweight photovoltaic (PV) devices manufactured via high-throughput roll-to-roll processes. In order to achieve higher power conversion efficiencies, it is necessary to approach the radiative limit via suppression of non-radiative recombination losses. Herein, we performed a systematic voltage loss analysis for a typical low-temperature processed, flexible PSC in n-i-p configuration using vacuum deposited C60 as electron transport layer (ETL) and two-step hybrid vacuum-solution deposition for CH3NH3PbI3 perovskite absorber. We identified the ETL/absorber interface as a bottleneck in relation to non-radiative recombination losses, the quasi-Fermi level splitting (QFLS) decreases from ~1.23 eV for the bare absorber, just ~90 meV below the radiative limit, to ~1.10 eV when C60 is used as ETL. To effectively mitigate these voltage losses, we investigated different interfacial modifications via vacuum deposited interlayers (BCP, B4PyMPM, 3TPYMB, and LiF). An improvement in QFLS of ~30–40 meV is observed after interlayer deposition and confirmed by comparable improvements in the open-circuit voltage after implementation of these interfacial modifications in flexible PSCs. Further investigations on absorber/hole transport layer (HTL) interface point out the detrimental role of dopants in Spiro-OMeTAD film (widely employed HTL in the community) as recombination centers upon oxidation and light exposure.

[Display omitted] • P(VDF-TRFE) boosts Spiro-OMeTAD-based power conversion efficiency (PCE) to 24.1%. • P(VDF-TRFE)-integrated cells retain > 90 % PCE for 45 days under ambient conditions. • P(VDF-TRFE)-integrated cells retained 94% PCE after 1080-hour light-soaking. • Robust bonding between P(VDF-TRFE) and Li-TFSI/TBP enhances HTL film quality. This study demonstrates the transformative impact of incorporating poly(vinylidene fluoride-co-trifluoroethylene) P(VDF-TRFE) as an additive in the hole transport layer (HTL) of 2,2′,7,7′-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro-OMeTAD). The P(VDF-TRFE) additive forms resilient coordination bonds with 4- tert -butylpyridine (TBP) and lithium bis(trifluoromethanesulfonyl)imide additives, which mitigates TBP evaporation and improves Spiro-OMeTAD film quality. In addition, we observed improvements in solar cell current–voltage characteristics consistent with increased Spiro-OMeTAD conductivity and suppressed non-radiative recombination at the HTL/perovskite interface. P(VDF-TRFE)-integrated devices exhibit an increment in power conversion efficiency (PCE) up to 24.1 % (reverse scan) from a reference PCE of 21.4 %. Furthermore, the unencapsulated P(VDF-TRFE)-integrated devices demonstrate improved stability, retaining over 90 % PCE after 45 days in an ambient atmosphere in the dark and 94 % PCE after 1080 h of continuous light-soaking in a nitrogen environment. This work demonstrates how additive engineering, as exemplified by P(VDF-TRFE), can effectively address stability and performance challenges within Spiro-OMeTAD in perovskite solar cells. [ABSTRACT FROM AUTHOR]

The possibility to manufacture perovskite solar cells (PSCs) at low temperatures paves the way to flexible and lightweight photovoltaic (PV) devices manufactured via high-throughput roll-to-roll processes. In order to achieve higher power conversion efficiencies, it is necessary to approach the radiative limit via suppression of non-radiative recombination losses. Herein, we performed a systematic voltage loss analysis for a typical low-temperature processed, flexible PSC in n-i-p configuration using vacuum deposited C60 as electron transport layer (ETL) and two-step hybrid vacuum-solution deposition for CH3NH3PbI3 perovskite absorber. We identified the ETL/absorber interface as a bottleneck in relation to non-radiative recombination losses, the quasi-Fermi level splitting (QFLS) decreases from ~1.23 eV for the bare absorber, just ~90 meV below the radiative limit, to ~1.10 eV when C60 is used as ETL. To effectively mitigate these voltage losses, we investigated different interfacial modifications via vacuum deposited interlayers (BCP, B4PyMPM, 3TPYMB, and LiF). An improvement in QFLS of ~30–40 meV is observed after interlayer deposition and confirmed by comparable improvements in the open-circuit voltage after implementation of these interfacial modifications in flexible PSCs. Further investigations on absorber/hole transport layer (HTL) interface point out the detrimental role of dopants in Spiro-OMeTAD film (widely employed HTL in the community) as recombination centers upon oxidation and light exposure. [ABSTRACT FROM AUTHOR]

A set of OASs with various side chains are applied as passivators to regulate interfacial band alignment, decrease defect density, and increase hydrophobic property. As a consequence, PSCs passivated with TOAC bearing a Si-O-CH 3 side chain achieve an increase in stability and PCE from 16.66% to 20.55%. [Display omitted] • Studying passivation effects via using a set of OASs with various side chains. • TOAC bearing a Si-O-CH 3 side chain leads to superior defect passivation, interfacial band alignment and hydrophobic property. • TOAC-treated PSCs show an increase in mean PCE from 16.62% to 20.06%. • The unencapsulated PSCs with TOAC treatment achieve excellent high-humidity stability. The extreme vulnerability of hybrid perovskite solar cells (PSCs) to moisture greatly limits the realization of their full potential. Here, we propose an efficient strategy to reinforce the efficiency and the ambient stability of PSCs via employing a series of octadecyl ammonium salts (OASs): octadecyl trimethyl ammonium chloride (OTAC), octadecyl dimethyl benzyl ammonium chloride (ODBAC), and 3-(trimethoxysilyl)propyl octadecyldimethyl ammonium chloride (TOAC), as passivating agents. Among these OASs, TOAC bearing a trimethoxysilane (Si-O-CH 3) side chain group most efficiently promoted the efficiency along with the high-humidity stability of PSC devices. TOAC significantly passivated the defects, assisted better energy-level alignment and facilitated charge carrier transport in the devices. The TOAC-passivated PSCs exhibited an increase in the average PCE from 16.62 ± 0.56 % to 20.06 ± 0.68 % with a substantially enhanced fill factor of 80.10 ± 1.82 %. Furthermore, the unencapsulated TOAC-passivated PSCs preserved 90 % of their performance after storage in ambient conditions (25–30 ℃, 50–70 % relative humidity) for 300 h. When no OAS passivator was introduced, the devices were losing more than 74 % of their starting PCE after 150 h. The Si-O-CH 3 groups side-chained to the OAS molecules were capable of supporting superior protection to the PSC devices against the permeation of high-moisture. Thereupon, the application of multifunctional octadecyl ammonium salt molecules to passivate defects and tailor the interface energy-level alignment in PSCs offers an encouraging staging to upgrade the PV performance of PSCs. [ABSTRACT FROM AUTHOR]

• Interfacial molecular stacking is optimized by a symmetric DDS molecule. • The DDS exhibits defect passivation capability and hydrophobicity. • A suitable intermediate energy level is achieved by DDS modification at the interface. • Carrier transfer and extraction are promoted by the DDS interlayer. • The PCE increases from 21.05% to 24.02% with a high fill factor of 84.0%. The non-radiative charge carrier recombination loss at the surface and interface of the perovskite layers in perovskite solar cells (PSCs) is the main cause of their limited power conversion efficiency (PCE). Here we propose an efficient strategy to minimize the non-radiative recombination by introducing symmetric molecules with regular arrangement at the interface between the perovskite layer and hole transport layer (HTL). One end of the symmetric molecule gets in a close contact with the terminal groups of the molecules in the HTL, while the other end promotes connection with the perovskite, resulting in an enhanced interfacial electrical contact and a better valence band energy-level alignment for efficient hole extraction. In contrast, introducing similar but asymmetrical molecules forms a dimer structure and mismatched energy levels at the interface region, which is detrimental to the carrier transport. The best-performing planar PSC with the symmetric molecular modification exhibited an increase in the PCE from 21.05% to 24.02% with a substantially enhanced fill factor of 84.0%, which can be ascribed to the synergistic effects of surface defect passivation and reduction in the interfacial energy barrier. Furthermore, the corresponding unencapsulated PSC retained 80% of the original PCE after 4,000 h of aging in dry air. [ABSTRACT FROM AUTHOR]

Lead chalcogenide colloidal quantum dot solar cells (CQDSCs) have the potential to revolutionize the field of light-to-electricity conversion with their exceptional optoelectronic properties. Unfortunately, realizing their full potential has been hindered by persistent and poorly understood limitations in fill factor (FF) and open-circuit voltage (V oc) losses. In this study, we performed a systematic numerical analysis of practical PbS CQDSCs to identify the root causes of FF and V oc losses in the current development stage, and to provide a clear and feasible roadmap for achieving a PCE of more than 20% in future development stages. Our analysis revealed that the highly effective route for enhancing the current 10% device is to initially modify the internal resistances, resulting in a significant reduction in FF losses to 15%, followed by systematic optimization of surface recombination velocities in the absorber layer and the absorber/hole transfer layer (HTL) interface, which can generate a V oc improvement of 3.76%, ultimately leading to a near-15% PCE. To further elevate PCE to unprecedented heights, we identified the precise regulation of surface excess charge densities at the absorber/HTL interface and the HTL/back contact interface as critical factors. By finely tuning these performance-limiting factors, we demonstrated the feasibility of achieving over 20% PCE, with minimal V oc loss of 318.10 mV and almost negligible FF loss of 6.08% in PbS CQDSCs. Our investigation provides crucial insights into the causes of FF and V oc losses in PbS CQDSCs and offers a clear pathway for future progress in this rapidly evolving field. [ABSTRACT FROM AUTHOR]

With the modulation of halogen of phenylethylamine, more stabilized tin halide perovskite and efficient charge transfer around the I-site and PEA+ mocule are achieced. The corresponding device achieves a notable improved power conversion efficiency of 11.94% with superior operational stability. [Display omitted] • Halogen engineering of phenylethylamine in tin halide perovskite was investigated. • Introduction of PEABr-I reduced the residual strain and stabilized the lattice. • The halide engineering decreased the formation energy of overall 2D/3D structure. • The target devices obtained a PCE of 11.94 % and a V oc of 0.81 V. • The unencapsulated devices showed superior operational stability. Stability is one of the key factors limiting the development of lead-free tin halide perovskite solar cells (TPSCs). Large organic bulky phenethylammonium ions (PEA+) have been widely introduced in TPSCs to regulate the dimensionality and film growth of perovskite. However, the mismatch in ionic radius of halogen ions could compromise the structural stability. Here, we report the halogen engineering of bulky additives in tin perovskites and their effect on the lattice stability and device performance. It was revealed that partial substitution of PEAI with PEABr could improve the structural stability as well as the charge transfer by the density functional theory calculations. A reduced residual strain along the (h 00) planes and improved crystallinity was observed after the introduction of PEABr. The halogen engineering reduced the defect density remarkably and inhibited the non-radiative recombination. As a consequence, the target inverted FA 0.75 MA 0.25 SnI 2.75 Br 0.25 (FA = formamidinium, MA = methylammonium) TPSCs obtained a power conversion efficiency (PCE) of 11.94 % with an open-circuit voltage (V oc) of 0.81 V, which was significantly higher than that of the device in absence of PEABr (PCE of 9.79 % and V oc of 0.75 V). Meanwhile, the unencapsulated devices maintained 94 % of the initial PCE after 2040 h storage in the N 2 atmosphere. [ABSTRACT FROM AUTHOR]

[Display omitted] • The 5PFP-Br is used as a double-interface passivator for PSCs. • The ETL with 5PFP-Br passivation has higher conductivity and electron mobility. • The perovskite with 5PFP-Br passivation has lower interfacial carrier defect state. • The PCE of the treated device increased from 18.09% to 21.15%. • The device based 5PFP-Br double-interface passivator have good stability. In order to obtain high power conversion efficiency and high stability perovskite solar cells, many innovative optimization schemes have been proposed. Thereinto, the interface modification become an effective way to improve the performance of device. Here, A dual-interface passivation by 2, 3, 4, 5, 6-pentafluorophenylammonium bromide-based (5PFP-Br) is used to optimize the performance of device with the structure of ITO/SnO 2 /perovskite/PTAA/Ag. We design the 5PFP-Br layer at SnO 2 /perovskite and perovskite/PTAA interface respectively. The results show that the interface contact between perovskite and charge transport layer is improved obviously. At the same time, the density of carrier transport defect states in the device is reduced, thus reducing the non-radiative recombination of carriers. Meanwhile, the 5PFP-Br layer at perovskite/PTAA interface can effectively passivate Pb defects and reduce the number of grain boundaries in perovskite film, and increase the carrier transfer and collection efficiency. Finally, 5PFP-Br double-interface passivation can further optimize and improve the performance of device. The device based 5PFP-Br double-interface passivation presents an increased efficiency from 18.09% to 21.15%, where FF is raised from 73.30% to 80.04%. At the same time, unpackaged device can still be maintained to more than 90% efficiency after about 1200 h at 25 °C and 25%RH. [ABSTRACT FROM AUTHOR]

The photovoltaic performance of C/O/S-doped hexagonal boron nitride (h-BN) quantum dots (QDs) is studied using density functional theory. Doping leads to occupied or unoccupied midgap states in h-BN QDs, resulting in a redshift in their absorption spectra. C-doping provides better charge transfer capability than S/O-doping. In addition, C-doping reduces the open-circuit voltage, light collection efficiency, fill factor, and driving forces of electron injection and reduction of h-BN QD. However, the fast non-radiative recombination deteriorates the energy conversion of C-doped h-BN QDs. The current study provides evidence for the rational design of photocatalytic devices based on h-BN QDs. [Display omitted] • S- and O-doping are not adequate for improving energy conversion of h-BN QDs. • C-doping offers suitable energy levels for the energy conversion of h-BN QDs • C-doping lowers the photovoltaic performance of h-BN QDs. [ABSTRACT FROM AUTHOR]

Inverted perovskite solar cells (inverted-PSCs) have exhibited advantages of longer stability, less hysteresis, and lower fabrication temperature when compared to their regular counterparts, which are important for industry commercialization. Because of the great efforts that have been conducted in the past several years, the obtained efficiency of inverted-PSCs has almost caught up with that of the regular ones, 25.0% versus 25.7%. In this perspective, the recent studies on the design of high-performance inverted-PSCs based on diverse hole transport materials, as well as device fabrication and characterization are first reviewed. After that, the authors moved on to the interface and additive engineering that were exploited to suppress the nonradiative recombination. Finally, the challenges and possible research pathways for facilitating the industrialization of inverted-PSCs were envisaged., Competing Interests: The authors declare no conflicts of interest., (© 2023 The Authors. Exploration published by Henan University and John Wiley & Sons Australia, Ltd.)

Copyright of Momento: Revista de Física is the property of Universidad Nacional de Colombia, Departamento de Fisica 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.)

[Display omitted] • A piperidine-based modulator ClEP was designed to passivate multi-type defects in MAFA perovskites. • The multifunctional ClEP helps perovskites crystallize in printable mesoscopic perovskite solar cells. • The performance of ClEP-modified printable mesoscopic PSCs is increased to 17.08% due to the better crystallization and less defects. Printable mesoscopic perovskite solar cells (PSCs) have received extensive attention due to their convenient large-area fabrication and good stability. The further improvement of the power conversion efficiency (PCE) of such simplified PSC configuration is limited by the low open circuit voltage (V OC). The high density of defects at grain boundaries of perovskites inside the mesoporous scaffold can cause severe nonradiative recombination, which have negative effects on V OC. Additive engineering has demonstrated advantages in improving the perovskite crystallization inside the pores, passivating the defects of perovskite and enhancing the performance of printable mesoscopic PSCs. Herein, we introduce a multifunctional modulator 1-(2-Chloroethyl) piperidine hydrochloride (ClEP) as an additive into the perovskite precursor solution. Benefiting from the strong interaction between ClEP and perovskite, it can interact with non-coordinating ions and defect states to achieve multi-defect passivation. As a result, the V OC of the printable mesoscopic PSC increases from 895.25 mV to 982.24 mV and the ClEP-treated printable mesoscopic PSC reaches a champion PCE of 17.08%. This work provides a new approach for developing efficient printable mesoscopic PSCs. [ABSTRACT FROM AUTHOR]

A phenethylamine hydroiodide derivative CF 3 PEAI was utilized to passivate the tin halide perovskite surface to reduce the interfacial voltage loss via strain relaxation and non-radiative recombination inhibition. [Display omitted] • CF 3 PEAI was applied to inhibit nonradiative recombination in tin perovskite. • The device achieved high open-circuit voltage (0.73 V) with PC 61 BM. • The density of defect states and micro-strain were dramatically reduced. • The long-term stability was greatly enhanced via the post-treatment. Tremendous attention has been given to tin halide perovskite solar cells (TPSCs) due to the lower toxicity and similar electronic configuration compared with the lead perovskites. Nevertheless, on account of the intrinsic low bandgap, high defect density and surface/interface non-radiative recombination, the open-circuit voltage loss (V loss) of TPSCs is comparatively large in all semiconductor solar cells. Herein, a hydrophobic bulky molecule of 3-(trifluoromethyl) phenethylamine hydroiodide (CF 3 PEAI) was utilized to passivate the lead-free perovskite surface by post-deposition treatment. The V loss of the corresponding PSC devices was significantly reduced to afford a high open-circuit voltage (V oc) up to 0.73 V with a power conversion efficiency (PCE) of 10.35% in conjunction with the broadly utilized (6,6)-Phenyl C 61 butyric acid methyl ester (PC 61 BM). Additionally, the CF 3 PEAI interlayer expressively suppressed the interfacial non-radiative recombination accompanying with extending photoexcited carrier lifetime. The formation of oriented 2D Sn-based perovskite could also facilitate the vertical charge-carrier transportation and improve the efficiency of Sn-based PSCs. The density of defect states and the amount of mid-gap states required to be filled were both dramatically reduced. Meanwhile, the surface reconstruction can effectively relax the tensile surface strain with the phenethyl ammonium iodide ligands. Therefore, this surface passivation strategy contributes to the development of high-quality lead-free perovskite film with low internal defects and residual stress. [ABSTRACT FROM AUTHOR]

[Display omitted] • GABr as bulk modifier enhance the performance of wide-bandgap solar cells (2.25 eV). • GABr modulated crystallization and comprehensively healed charged defects. • State-of-the-art FAPbBr 3 solar cell with GABr yielded a record V OC of 1.639 V. • Demonstrate the potential of wide-bandgap perovskite for all-perovskite MTJSCs. The bromide-based perovskites with wide bandgap have attracted particular interests for the potential ability to serve as front sub-cells of monolithic all-perovskite triple junction tandem solar cells. However, non-radiative recombination induced by crystal defects could cause the massive open-circuit voltage (V OC) losses, which severely disserves the performance of bromide-based perovskite solar cells. Hence, we incorporated guanidinium bromide (GABr) to modulate crystallization and heal charged defects of FAPbBr 3 -based solar cells. The introduction of GABr provides a non-wetting surface and suppresses heterogeneous nucleation, leading to larger grain size. Notably, nitrogen (N) atoms from GA+ cations are in two differently charged environments, which are ionized ammonium group (–NH 3 +) and unsaturated N atoms in form of amine or imine group (–NH 2 or = NH). Thus, GA+ cations simultaneously heal both positively and negatively charged defects through multi-reactive sites with perovskite. Consequently, introduction of GABr releases microstrain and strengthens lattice structure, further transforms the perovskite from charge-rich to charge-natural region, which comprehensively leads to suppress non-radiative recombination. As a result, the high-quality planar FAPbBr 3 -based device yielded a PCE of 8.92% with a champion V OC of 1.639 V, which is the highest value among FAPbBr 3 solar cells up to date. [ABSTRACT FROM AUTHOR]