Two-dimensional transition metal dichalcogenides for lead halide perovskites-based photodetectors: band alignment investigation for the case of CsPbBr3/MoSe2

The distinguished electronic and optical properties of lead halide perovskites(LHPs)make them good candidates for active layer in optoelectronic devices.Integrating LHPs and two-dimensional(2 D)transition metal dichalcogenides(TMDs)provides opportunities for achieving increased performance in heterostructured LHPs/TMDs based optoelectronic devices.The electronic structures of LHPs/TMDs heterostructures,such as the band offsets and interfacial interaction,are of fundamental and technological interest.Here CsPbBr3 and MoSe2 are taken as prototypes of LHPs and 2 D TMDs to investigate the band alignment and interfacial coupling between them.Our GGA-PBE and HSE06 calculations reveal an intrinsic type-II band alignment between CsPbBr3 and MoSe2.This type-II band alignment suggests that the performance of CsPbBr3-based photodetectors can be improved by incorporating MoSe2 monolayer.Furthermore,the absence of deep defect states at CsPbBr3/MoSe2 interfaces is also beneficial to the better performance of photodetectors based on CsPbBr3/MoSe2 heterostructure.This work not only offers insights into the improved performance of photodetectors based on LHPs/TMDs heterostructures but it also provides guidelines for designing high-efficiency optoelectronic devices based on LHPs/TMDs heterostructures.

Achieving 20% photovoltaic efficiency by manganese doped methylammonium lead halide perovskites

We report a transition metal such as manganese doped methylammonium lead halide perovskite(MA(Pb:Mn)I_(3)) solar cell with an power conversion efficiency(PCE) over 20%. The rational design and fabrication of MA(Pb:Mn)I3 lead to the enhancements of all the photovoltaic parameters. To incorporate Mn can effectively eliminate the trap-assist and bi-molecular recombination. The photo-absorption ability at shorter wavelengths(i.e., less than 500 nm) and charge carrier lifetime can be elaborated. More importantly, the existence of the Mn^(2+)-I~--Mn^(3+)motif contributes for the double exchange effect, giving rise to the charge/spin transport. By a combination of linearly and circularly polarized photo-excitations, we have explicitly determined the role of intrinsic spin–orbit coupling(SOC) in MA(Pb:Mn)I_(3). More dark states are expected to be available for the photocurrent generation. This study may pave the way for deep understandings of transition metals doped hybrid perovskites for highly efficient solar cell applications.

Is machine learning redefining the perovskite solar cells?

Development of novel materials with desirable properties remains at the forefront of modern scientific research.Machine learning(ML),a branch of artificial intelligence,has recently emerged as a powerful technology in optoelectronic devices for the prediction of various properties and rational design of materials.Metal halide perovskites(MHPs)have been at the centre of attraction owing to their outstanding photophysical properties and rapid development in solar cell application.Therefore,the application of ML in the field of MHPs is also getting much attention to optimize the fabrication process and reduce the cost of processing.Here,we comprehensively reviewed different applications of ML in the designing of both MHP absorber layers as well as complete perovskite solar cells(PSCs).At the end,the challenges of ML along with the possible future direction of research are discussed.We believe that this review becomes an indispensable roadmap for optimizing materials composition and predicting design strategies in the field of perovskite technology in the future.

新型钙钛矿太阳能电池的研究进展

太阳能光伏发电是解决目前日益严重的能源与环境问题的一种有效手段,在最近几年里,新型钙钛矿太阳能电池得到迅猛发展,其最高光电转换效率已经达到20%,已成为可再生能源领域的研究热点之一。钙钛矿太阳能电池是以具有钙钛矿结构的有机-金属卤化物等作为核心光吸收、光电转换、光生载流子输运材料的太阳能电池,具有能量转换高和成本低的优点且其核心光电转换材料具有廉价、容易制备的特点,因此获得了学术界的特别关注。首先总结了钙钛矿太阳能电池的结构与原理,然后综述了钙钛矿太阳电池在结构和材料方面的最新研究进展,特别是无铅钙钛矿太阳能电池的一些研究,最后分析了钙钛矿太阳能电池的发展趋势及发展中亟需解决的问题。

金属卤化铅钙钛矿可见光催化研究进展

由化石能源消耗所引发的能源危机与环境污染,已成为了人类社会可持续发展亟待解决的一个首要问题。可见光催化技术利用太阳光为能源,通过光解水制氢、CO_(2)还原、污染物降解等过程为从根本上解决上述问题提供了一个有效途径,对可持续发展战略具有重要意义。金属卤化铅钙钛矿(lead metal halide perovskite,LMHP)型光催化剂因其多样的晶体结构、合适的禁带宽度及丰富的空位,表现出优异的光电性能,为实现光催化剂的性能调控提供了多种手段,成为了当前的一个研究热点。近年来,金属卤化铅钙钛矿的研究与应用发展非常迅速,特别是在太阳能驱动的应用中,取得了一系列成果。详细综述了金属卤化铅钙钛矿型光催化材料在可见光催化能源开发和环境污染治理领域的研究进展,为进一步开发环保高效的光催化剂新材料提供新的思路。

铅基卤化物钙钛矿纳米晶掺杂研究进展

铅基卤化物钙钛矿CsPbX_(3)(X=Cl,Br,I)半导体纳米晶由于具有窄半峰宽、可调发射波长、高荧光量子产率等优异的光电特性,在发光二极管、激光器、太阳能电池等领域有很广阔的应用前景。通过化学掺杂的方法将掺杂原子引入到钙钛矿纳米晶中,可以改变纳米晶的光电性质,包括带隙宽度、光致发光强度、荧光量子产率和稳定性,掺杂原子种类和浓度也会影响钙钛矿纳米晶的电子能带结构和荧光特性,因此针对钙钛矿纳米晶的掺杂成为了近年来的研究热点。ABX_(3)型纳米晶的A/B/X位均可被杂质原子取代,研究发现,B位掺杂对纳米晶性质的影响更为明显,综述了铅基卤化物钙钛矿纳米晶的B位掺杂方法、机理及对其结构和光电性能的影响,掺杂元素主要包括Mn,Ln,Sn和碱土金属等。掺杂上述离子可有效改善钙钛矿纳米晶光学性能和稳定性,并进一步推动其实际应用。

环境友好型无铅卤化物钙钛矿太阳能电池研究进展

ABX3(A为甲胺、甲脒等有机离子或铯离子,B为铅或锡等金属离子,X为溴、碘等卤化物离子)卤化物钙钛矿材料具有优异的光电特性,是当前太阳能电池研究的前沿和热点之一。然而,这类太阳能电池普遍面临含毒性元素铅和稳定性差等问题,极大地阻碍了钙钛矿太阳能电池商业化应用进程。因此,发展新型高效无铅钙钛矿太阳能电池势在必行。本文评述了环境友好型无铅卤化物钙钛矿太阳能电池的最新研究动态和进展,探讨了该类太阳能电池的制备、性能及其稳定性等问题,展望了其未来发展趋势。