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Halide perovskite single crystals (HPSCs) provide a unique platform to study the optoelectronic properties of such emerging semiconductor materials, while the temperature induced crystal growth method often has an increased solute integration speed and/or unavoidable solute consumption, resulting in a soaring or slumping crystal growth rate of HPSCs. Here, we developed a universal and facile solvent-volatilization-limited-growth (SVG) strategy to finely control the crystal growth rate by the fine-control-valve for high quality crystal grown through solution processes. The grown HPSCs by SVG method exhibited a record low trap density of 2.8 × 108 cm−3 and a high charge carrier mobility-lifetime product (μτ product) of 0.021 cm2/V, indicating the excellent crystal quality. The crystal surface defects were further passivated by oxygen suppliers as Lewis base, which led to a reduction of surface leakage current by two times when using for low dose rate X-ray detection. Such HPSC X-ray detector displayed a high sensitivity of 1274 µC/(Gyair cm2) with a lowest detectable dose rate of 0.56 μGyair/s under 120 keV hard X-ray. Further applications including alloy composition analysis and metal flaw detection by HPSC detectors were also demonstrated, which not only shows the bright future for product quality inspection and non-destructive materials analysis, but also paves the way for growing high quality single crystals and fabricating polycrystalline films.

Methylammonium lead tribromide (MAPbBr3) perovskite crystals have attracted significant attention due to their attractive performance in various optoelectronic applications such as solar cells, light-emitting devices, photodetectors, and recently in X-ray detectors. In this study, we demonstrate a possible use of perovskite-based devices for detection of charged particles (which can be applied in basic scientific research, health physics, and environmental analysis) and investigate the mechanism of fundamental charge transport inside perovskite crystals. It was found that inexpensive MAPbBr3 single crystals could be used for measuring the energy spectrum of charged particles through direct collection of the produced charge. After fitting the plot of the centroid peak position versus voltage with the Hecht equation for single-polarity charge transport, the obtained hole mobility-lifetime product was in the range of (0.4–1.6)×10−3 cm2/V.

Cesium-based trihalide perovskites have been demonstrated as promising light absorbers for photovoltaic applications due to its superb thermal stability. However, the large energy losses (Eloss) in the conversion from photons to electrons observed in many inorganic perovskite solar cells has become a major hindrance impairing the ultimate efficiency of these devices. Here, we report an effective and reproducible method of modifying the interface between a CsPbI2Br absorber and polythiophene hole-acceptor to minimize the Eloss. We demonstrate that polythiophene, deposited on the top of CsPbI2Br, can significantly reduce electron-hole recombination within the perovskite, which is due to the electronic passivation of surface defect states. In addition, the interfacial properties are improved by a simple annealing process, leading to significantly reduced energy disorder in polythiophene and enhanced hole-injection into the hole-acceptor. Consequently, a record power conversion efficiency (PCE) of 12.09% in inorganic perovskite solar cells is obtained, together with a high open-circuit voltage (VOC) over 1.3 V, under 100 mWcm-2 AM1.5G solar illumination. This method provides a new route to further improve the efficiency of perovskite solar cells by minimizing the Eloss.

To fabricate efficient solar cells, it is crucial to control the nanoscale morphology of the bulk-heterojunction (BHJ) film, in which the thermal and morphological stability is an important issue. In this article, aqueous-solution-processed hybrid photovoltaic devices from poly(1,4-naphthalene vinylene) (PNV) and CdTe nanocrystals (NCs) are fabricated and a power conversion efficiency (PCE) of 1.74% under AM1.5G illumination is achieved. Furthermore, we demonstrate the high thermal stability of hybrid solar cells by investigating the evolution of hybrid films with prolonged annealing time and elevated temperature. Thermal annealing is necessary for converting PNV precursor to PNV and removing the ligands on CdTe NCs, which leads to the improvement of device performance. In particular, the prolonged annealing time and elevated temperature do not lower the PCE, because the interconnected CdTe networks are highly rigid and thereby suppress the excess phase separation of PNV, which is one of the main issues determining the long-term stability of polymer-based photovoltaic devices. This advantage is considered to promote the development of hybrid solar cells from various aqueous-solution-processed polymers and NCs.

Summary Solution-processed organic or organic–inorganic hybrid photovoltaic devices possess many advantages both in the commercial manufacture and daily operation, thus becoming competitive candidates of the next generation solar cells. To exert these advantages, this review summarizes the recent progresses in creating organic–inorganic hybrid solar cells, and in particular polymer–nanocrystals hybrid solar cells via aqueous-solution-processed approaches. The basic principles of the hybrid photovoltaic devices are illustrated first, which are essential for the effective photoelectric conversion. Then we focus on the achievement of the aqueous hybrid solar cells and the limiting factors of the power conversion efficiency (PCE). On this basis, different aqueous-solution-processed methods and the efforts to improve the PCE are presented in detail.