Antimony doped CsPbI_(2)Br for high-stability all-inorganic perovskite solar cells

All-inorganic perovskites,adopting cesium(Cs+)cation to completely replace the organic component of A-sites of hybrid organic–inorganic halide perovskites,have attracted much attention owing to the excellent thermal stability.However,all-inorganic iodine-based perovskites generally exhibit poor phase stability in ambient conditions.Herein,we propose an efficient strategy to introduce antimony(Sb^(3+))into the crystalline lattices of CsPbI_(2)Br perovskite,which can effectively regulate the growth of perovskite crystals to obtain a more stable perovskite phase.Due to the much smaller ionic radius and lower electronegativity of trivalent Sb^(3+)than those of Pb^(2+),the Sb^(3+)doping can decrease surface defects and suppress charge recombination,resulting in longer carrier lifetime and negligible hysteresis.As a result,the all-inorganic perovskite solar cells(PSCs)based on 0.25%Sb^(3+)doped CsPbI_(2)Br light absorber and screen-printable nanocarbon counter electrode achieved a power conversion efficiency of 11.06%,which is 16%higher than that of the control devices without Sb^(3+)doping.Moreover,the Sb^(3+)doped all-inorganic PSCs also exhibited greatly improved endurance against heat and moisture.Due to the use of low-cost and easy-to-process nanocarbon counter electrodes,the manufacturing process of the all-inorganic PSCs is very convenient and highly repeatable,and the manufacturing cost can be greatly reduced.This work offers a promising approach to constructing high-stability all-inorganic PSCs by introducing appropriate lattice doping.

Multifunctional dual-anion compensation of amphoteric glycine hydrochloride enabled highly stable perovskite solar cells with prolonged carrier lifetime

Throughout years,the two-step spin-coating process is the most common method to prepare organic lead halide perovskite materials.However,the short reaction time of dropping the solution at the second step means that PbI2 cannot be completely transformed into perovskite phase.To solve this problem,we report the introduction of glycine hydrochloride(GlyHCl)into the second step of the two-step spin-coating process to prepare a FA_(0.9)MA_(0.1)PbI_(3-x)%-GlyHCl perovskite material(namely FAMA-x%-GlyHCl,where FA=formamidinium,MA=methylammonium,and x%stands for the molar ratio of GlyHCl added in FA iodide/MA iodide(FAI/MAI)precursor solution).The Cl−ion in GlyHCl assists the formation ofα-phase perovskite,and the-COO−group coordinates with Pb2+cation in a bridging way,making up for the anion vacancy in perovskite lattice and resulting in high absorption intensity.The perovskite solar cells(PSCs)based on FAMA-9%-GlyHCl achieve a long carrier lifetime(527.0 ns),a photoelectric conversion efficiency(PCE)of 19.40%and good thermal stability,maintaining 85.8%of the initial PCE after being continuously heated at 60℃for 500 h.This study helps to solve the problem of incomplete reaction in the two-step spin-coating process and puts forward a new solution for preparing high coverage perovskite films with large grain size.

Unveiling non-radiative center control in CsPbBr_(3) nanocrystals:A comprehensive comparative analysis of hot injection and ligandassisted reprecipitation approaches

Metal-halide perovskite nanocrystals(NCs)have gained significant attention in the field of optoelectronic and photonic devices due to their promising applications.Despite their exceptional optical properties,the impact of different synthetic strategies on the fundamental nature of NCs,such as nonradiative recombination centers,remains poorly understood.In this study,we investigated the photophysical properties of CsPbBr_(3) NCs synthesized using two distinct methods,hot injection and ligand-assisted reprecipitation,at the individual particle level.We observed different blinking behaviors under specific photoexcitation power densities and proposed,through intensity-lifetime analysis and Monte-Carlo simulations,that these different synthetic strategies can fabricate NCs with similar crystal structures but distinct surface quenchers with varying energy levels,which significantly affected the photo-induced blinking-down and blinking-up behaviors in individual NCs.Our findings indicate a practical and feasible approach for controlling defect engineering in perovskite NCs,with significant implications for their use in optoelectronic and other technological applications.

Reducing surficial and interfacial defects by thiocyanate ionic liquid additive and ammonium formate passivator for efficient and stable perovskite solar cells

Organic–inorganic metal halide perovskites have attained extensive attention owing to their outstanding photovoltaic performances,but the existence of numerous defects in crystalline perovskites is still a serious constraint for the further development of perovskite solar cells(PSCs).In particular,the rapid crystallization guided by anti-solvents leads to plenty of surficial and interfacial defects in perovskite films.Herein,we report the adoption of a pseudo-halide anion based ionic liquid additive,1-butyl-3-methylimidazolium thiocyanate(BMIMSCN)for growing ternary cation(CsFAMA,where FA=formamidinium and MA=methylammonium)perovskites with large-scale crystal grains and strong preferential orientation via the enhanced Ostwald ripening.Meanwhile,a novel halide-free passivator,benzylammonium formate(BAFa),was employed as a buffering layer on the perovskite films to suppress surface-dominated charge recombination.As a result,the cooperative effects of BMIMSCN additive and BAFa passivator lead to significant enhancements on fluorescence lifetime(from 79.41 to 201.01 ns),open-circuit voltage(from 1.13 to 1.19 V),photoelectric conversion efficiency(from 18.90%to 22.33%).Moreover,the BMIMSCN/BAFa-CsFAMA PSCs demonstrated greatly improved stability against moisture and heat.This work suggests a promising strategy to improve the quality of perovskite materials via reducing the surficial and interfacial defects by the synergistic effects of lattice doping and interface engineering.

Effects of local matrix environment on the spectroscopic properties of ensemble to single-particle level carbon dots

Carbon dots(CDs), because of their unique properties, are being rapidly developed as important luminescent materials for imaging, sensing, and use in photonic devices. However, most of the reported fundamental properties of the CDs are results of investigations conducted in the solution state, which may be completely different from those conducted in the solid state. In this work, we study the luminescence properties, photostability, and the dynamics of CDs in different matrix environments, from ensemble to the single-particle level. We observed that the properties associated with the emission centers and photostability of CDs were extremely sensitive to the local chemical environment. A better understanding of the dependence of the spectroscopic properties of CDs on the complex local chemical environment is an important step toward finding new ways of controlling the optical properties of CDs and optimizing their use in various applications.