Organic–inorganic hybrid perovskites have attracted considerable attention due to their superior optoelectronic properties. Traditional one‐step solution‐processed perovskites often suffer from defects‐induced nonradiative recombination, which significantly hinders the improvement of device performance. Herein, treatment with green antisolvents for achieving high‐quality perovskite films is reported. Compared to defects‐filled ones, perovskite films by antisolvent treatment using methylamine bromide (MABr) in ethanol (MABr‐Eth) not only enhances the resultant perovskite crystallinity with large grain size, but also passivates the surface defects. In this case, the engineering of MABr‐Eth‐treated perovskites suppressing defects‐induced nonradiative recombination in perovskite solar cells (PSCs) is demonstrated. As a result, the fabricated inverted planar heterojunction device of ITO/PTAA/Cs0.15FA0.85PbI3/PC61BM/Phen‐NADPO/Ag exhibits the best power conversion efficiency of 21.53%. Furthermore, the corresponding PSCs possess a better storage and light‐soaking stability.

In the past years, hybrid perovskite materials have intrigued great attention due to its superior optoelectronic properties. In this study, we report the utilization of cobalt (Co 2+ ) with a cationic radius of 70 pm, to partially substitute Pb 2+ with a cationic radius of 119 pm, for developing novel hybrid perovskite materials, CH 3 NH 3 Pb 1-x Co x I 3 (where x is nominal ratio, x = 0, 0.1, 0.2 and 0.4). It is found that the CH 3 NH 3 Pb 1-x Co x I 3 (where x = 0.1 and 0.2) thin films possess the cubic crystal structure with superior thin film morphology and larger grain size (>1 m), which is significantly different from pristine CH 3 NH 3 PbI 3 thin film, which possesses the tetragonal crystal structure, with smaller grain size (~200 nm). However, the CH 3 NH 3 Pb 0.6 Co 0.4 I 3 thin film possesses a mixture of the tetragonal and cubic phases with inferior thin film morphology. In addition, it is found that the 3d orbital of Co 2+ ensures higher electron mobilities and electrical conductivities of the CH 3 NH 3 Pb 1-x Co x I 3 thin films than those of pristine CH 3 NH 3 PbI 3 thin film. As a result, a power conversion efficiency of 21.43% is This article is protected by copyright. All rights reserved. 2 observed from perovskite solar cells fabricated by the CH 3 NH 3 Pb 0.9 Co 0.1 I 3 thin film. Thus, our finding of utilization of Co partially substitute Pb to tune physical properties of hybrid perovskite materials provides a facile way to boost device performance of perovskite solar cells.

In this work, room-temperature operated ultrasensitive solution-processed perovskite photodetectors (PDs) with near infrared (NIR) photoresponse is reported. In order to enable perovskite PDs possessing extended NIR photoresponse, novel n-type low bandgap conjugated polymer, poly [(N,N'-bis(NDI-DPP), which has strong absorption in the NIR region, is developed and then employed in perovskite PDs. By formation of type II band alignment between NDI-DPP with single wall carbon nanotubes (SWCNTs), the NIR absorption of NDI-DPP has been exploited, which contributes to the NIR photoresponse for the perovskite PDs, where perovskite is incorporated with NDI-DPP and SWCNTs as well. In addition, SWCNTs incorporated with perovskite active layer can offer the percolation pathways for high charge carrier mobility, which tremendously boosts the charge transfer in the photoactive layer, and consequently improves the photocurrent in the visible region. As a result, the perovskite PDs exhibits the responsivities of ~400 mA/W and ~150 mA/W and the detectivities of over 6×10 12 Jones (1 Jones =1 cmHz 1/2 W -1 ) and over 2×10 12 Jones in the visible and NIR regions, respectively.Our work reports the development of perovskite PDs with NIR photoresponse, which is terrifically beneficial for the practical applications of perovskite PDs.

Solution-processed polymer PDs with a spectral response ranging from 350 nm to 2500 nm.