High‐quality perovskite single crystals with large size are highly desirable for the fundamental research and high energy detection application. Here, a simple and convenient solution method, featuring continuous‐mass transport process (CMTP) by a steady self‐supply way, is shown to keep the growth of semiconductor single crystals continuously stable at a constant growth rate until an expected crystal size is achieved. A significantly reduced full width at half‐maximum (36 arcsec) of the (400) plane from the X‐ray rocking curve indicates a low angular dislocation of 6.8 × 10⁶ cm⁻² and hence a higher crystalline quality for the CH₃NH₃PbI₃(MAPbI₃) single crystals grown by CMTP as compared to the conventional inverse temperature crystallization (ITC) method. Furthermore, the CMTP‐based single crystals have lower trap density, reduced by nearly 200% to 4.5 × 10⁹ cm⁻³, higher mobility increased by 187% to 150.2 cm² V⁻¹ s⁻¹, and higher mobility–lifetime product increased by around 450% to 1.6 × 10⁻³ cm² V⁻¹, as compared with the ITC‐grown reference sample. The high performance of the CMTP‐based MAPbI₃ X‐ray detector is comparable to that of a traditional high‐quality CdZnTe device, indicating the CMTP method as being a cost‐efficient strategy for high‐quality electronic‐grade semiconductor single crystals.

A PbI₂ phase is found to be inevitably formed at the interface in dual-source evaporated perovskite films that will block carrier transport.

Flash evaporation is a vacuum-based evaporation method that is particularly suitable to prepare perovskite films for solar cell devices. Growth pressure has been found to be a critical parameter for perovskite film growth. The transport-determined growth mechanism is discussed in detail. The dense MAPbI₃ films can be achieved only under a low growth pressure of 5 × 10⁻³ Pa, while a rough surface covered by step-like grains and voids is found for MAPbI₃ films grown under a high Ar pressure of 10 Pa. In addition, we found that the presence of PbI₂ phase in the perovskite films could suppress the growth of the grain size; by using precursors with a high MAI/PbI₂ ratio, evaporated MAPbI₃ films with grain sizes larger than 500 nm can be achieved. The average power conversion efficiency of the perovskite solar cells increased from 1.82% to 10.01% with increasing grain size, indicating the universal importance of controlling the perovskite grain size for the performance improvement of solar cells based on both solution and evaporated perovskite films.

The carriers’ behavior in neutral region (NTR) and space charged region (SCR) of Cu(In,Ga)Se₂ thin film based solar cells has been investigated by temperature dependent photoluminescence (PL-T), electroluminescence (EL-T) and current-voltage (IV-T) from 10 to 300 K. PL-T spectra show that three kinds of defects, namely V_Se, In_Cu and (In_Cu+V_Cu), are localized within the band gap of NTR and SCR of CIGS layer, corresponding to the energy levels of E_C-0.08, E_C-0.20 and E_C-0.25 eV, respectively. The In_Cu and (In_Cu+V_Cu) deep level defects are non-radiative recombination centers at room temperature. The IV-T and EL-T analysis reveals that the injection modes of electrons from ZnO conduction band into Cu(In,Ga)Se₂ layer are tunneling, thermally-excited tunneling and thermionic emission under 10-40, 60-160, and 180-300 K, respectively. At 10-160 K, the electrons tunnel into (In_Cu+V_Cu) and V_se defect levels in band gap of SCR and the drifting is involved in the emission bands at 0.96 and 1.07 eV, which is the direct evidence for a tunneling assisted recombination. At 180-300 K, the electrons are directly injected into the Cu(In,Ga)Se₂ conduction band, and the emission of 1.13 eV are ascribed to the transitions from the conduction band to the valence band.