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Post-polymerization modification (PPM) techniques are extremely beneficial in terms of designing well-defined functional polymers for various applications. In particular, metal-free PMM based on fl...

Due to the ultrafast crystallization process in the triple-source ligand-assisted reprecipitation (TSLARP) technique the [LyPbBrx] octahedra is easily distorted, resulting in anisotropic two-dimensional nanoplatelets (NPLs) with low photoluminescence quantum yield (PLQY) and poor stability. Unexpectedly, we obtain CsPbBr3 NPLs with PLQY approaching unity and high stability using the TSLARP technique through aging the metal-oleate precursors. We find that the significant enhancement of the PLQY is related to the change of solution chemistry of the Pb-oleate precursor in the aging process. While hybrid CsPbBr3@Cs4PbBr6 NPLs with low PLQY (28%) are formed with fresh Pb-oleate precursor, phase-pure CsPbBr3 NPLs with PLQY of 97.4% are obtained with the aged Pb-oleate precursor. A model that takes into account the transformation of the Pb-oleate in toluene from isolated molecules into clusters after aging is proposed to explain the phenomenon. Our finding highlights the importance of understanding the solution chemistry for the synthesis of the highly luminescent NPLs and provides a new way to break the "blue-wall" in perovskite light-emitting devices.

Metal halide perovskite quantum dots (QDs) hold great promise as building blocks for next-generation light emitting devices (LEDs). The preparation of perovskite QD films with high photoluminescence quantum yield (PLQY) is the key to realizing efficient LEDs. However, the conventional deposition method of spin-coating of pre-synthesized QD ink solutions results in perovskite QD films with low PLQY (typically

The last decade has witnessed the exploration of exceptional optoelectronic and photovoltaic properties of perovskite solar cells (PSCs) at the laboratory scale. Unfortunately, their sensitivity to moisture causes bulk degradation, hindering the commercialization of PSC devices. Despite the numerous strategies that have been developed to date in this field, effective passivation against moisture remains highly challenging. Here, we report a novel approach based on the incorporation of polyacetylene derivatives into the perovskite active layer to yield perovskite films with larger grains, lower defect density, and excellent robustness with respect to moisture. Moreover, it is revealed that the reduced trap-state density of these films is most likely due to the efficient coordination between the carboxylate moieties in the polymer and the undercoordinated Pb2+ in the perovskite. Upon adopting the polymer-doped perovskite as an active layer in inverted planar heterojunction PSCs with all-inorganic charge extraction layers, the power conversion efficiency (PCE) is improved to 20.41%, which is the highest value reported to date for this type of PSC to the best of our knowledge. Most importantly, the optimized device retained 90% of its initial PCE after aging in ambient air for 60 days due to its dual mechanism of moisture resistance. This work highlights an approach for developing high-performance PSCs with improved moisture stability and paves the way for their potential commercialization.

B-site doping of organic–inorganic perovskites is an effective way to improve its optoelectronic properties; however, it is rarely reported for perovskite single crystals. Here, we report the B-sit...

Metal halide perovskite quantum dots (QDs) hold great promise as building blocks for next-generation light emitting devices (LEDs). The preparation of perovskite QD films with high photoluminescence quantum yield (PLQY) is the key to realizing efficient LEDs. However, the conventional deposition method of spin-coating of pre-synthesized QD ink solutions results in perovskite QD films with low PLQY (typically45%) due to non-radiative recombination centers induced in the deposition process. Here, by utilizing the ionic nature and steric hindrance effect of the ionic liquid, we demonstrate an

Due to the ultrafast crystallization process in the triple-source ligand-assisted reprecipitation (TSLARP) technique the [L

Colloidal quantum dot (QD)-based photoelectrochemical (PEC) cells are cost-effective devices showing remarkable solar-to-fuel conversion efficiency. However, the extensive use of highly toxic elements (e.g. Pb and Cd) in QDs' synthesis and device fabrication is still a major challenge towards their practical development. Herein, we fabricate a solar-driven PEC cell based on environmentally friendly Mn-alloyed CuInS2 (MnCIS)/ZnS core/shell QDs, showing more favorable band alignment, efficient charge transfer, reduced charge recombination and lower charge transfer resistance with respect to the control device fabricated using unalloyed CuInS2 (CIS)/ZnS core/shell QDs. An unprecedented photocurrent density of ∼5.7 mA cm−2 with excellent stability was obtained for the as-fabricated MnCIS/ZnS core/shell QD-based PEC device when operated under standard one sun irradiation (AM 1.5G, 100 mW cm−2). These results indicate that the transition metal-alloyed environmentally friendly core/shell QDs are promising for next-generation solar technologies.

Bismuth iron oxide (BiFeO3) has attracted widespread attention in the field of photoelectrochemistry due to its special ferroelectric properties. However, its high charge recombination from defects and sluggish water oxidation kinetics limit the potential application. Herein, oxygen vacancies are first introduced in BiFeO3 thin films by Ar annealing to improve the bulk charge transfer efficiency. Subsequently, a p-type conductive poly(3, 4-ethylenedioxythiophene) (PEDOT) is employed to suppress the surface-defect-related recombination of photogenerated carriers and to form a p–n junction to increase the charge extraction efficiency. As a result, the photocurrent density of the optimized NiCoFe-Bi/PEDOT/BiFeO3 photoanode reaches 0.17 mA cm−2 at 1.23 V vs reversible hydrogen electrode (RHE) under simulated 1 sun irradiation for water oxidation, which is enhanced by six times compared with that of the photoanode without PEDOT modification. The photocurrent density is further improved to 0.23 mA cm−2 at 1.23 V vs RHE through polarization of the ferroelectric material. This study strongly suggests that surface passivation is an effective way to improve the activity of the BiFeO3 photoanode for solar water splitting.

All-inorganic cesium lead halide perovskites (CsPbX3, X = Cl, I, Br) have attracted great attention for developing high-performance photovoltaics due to their superb thermal stability. However, the short electron-hole diffusion lengths (LDs) in CsPbI2Br perovskite are the primary limiting factor for further improvement of the power conversion efficiencies (PCEs) of the CsPbI2Br solar cells. Herein, a simple yet effective method is reported to prolong the LDs in CsPbI2Br via codoping of Zn2+ and acetate (Ac−) ions (i.e., using Zn(Ac)2 as dopant). It is demonstrated that Zn2+ partially replaces Pb2+ to form a more stable black phase, and Ac− coordinates with Pb2+ to passivate the defects at the perovskite grain boundaries which reduces electron-hole recombination within the perovskite. As a result, the LDs of Zn(Ac)2 doped CsPbI2Br are greater than 1 μm, which is the first report on all-inorganic perovskites. The champion PCE of the CsPbI2Br solar cells is drastically increased from 12.31% to 14.93% upon doping with Zn(Ac)2, stemming mainly from the increased open-circuit voltage and fill factor. Furthermore, the non-encapsulated devices with Zn(Ac)2 doped CsPbI2Br show less than 10% efficiency loss after storage in dry air for 30 days.