PbI 2 -EMIMHSO 4 intermediates, finally enlarged the grain size, decreased the trap density, and relaxed the lattice strain of perovskite. The synergetic effects enable us to fabricate ambient blade-coating high-performance CsPbI 3 solar cells with PCEs as high as 20.01% under 1 sun illumination (100 mW cm −2 ) and 37.24% under indoor light illumination (1000 lux, 365 µW cm −2 ); both are the highest for the printed all-inorganic cells for corresponding applications. More importantly, the PCEs of CsPbI 3 -EMIMHSO 4 -based PSCs without any encapsulation retained 95% of the initial PCE value after 1000 h aging under ambient condition. Considering the simplicity and availability of this approach, our study offers an effective materials strategy to passivate crystal defect and regulate interfacial energy alignment for upscaling high-performance and long-term stable PSCs under ambient conditions.Research data are not shared.

Even though the perovskite solar cell has been so popular for its skyrocketing power conversion efficiency, its further development is still roadblocked by its overall performance, in particular long-term stability, large-area fabrication and stable module efficiency. In essence, the soft component and ionic–electronic nature of metal halide perovskites usually chaperonage large number of anion vacancy defects that act as recombination centers to decrease both the photovoltaic efficiency and operational stability. Herein, we report a one-stone-for-two-birds strategy in which both anion-fixation and associated undercoordinated-Pb passivation are in situ achieved during crystallization by using a single amidino-based ligand, namely 3-amidinopyridine, for metal-halide perovskite to overcome above challenges. The resultant devices attain a power conversion efficiency as high as 25.3% (certified at 24.8%) with substantially improved stability. Moreover, the device without encapsulation retained 92% of its initial efficiency after 5000 h exposure in ambient and the device with encapsulation retained 95% of its initial efficiency after >500 h working at the maximum power point under continuous light irradiation in ambient. It is expected this one-stone-for-two-birds strategy will benefit large-area fabrication that desires for simplicity.

The efficiency of earth‐abundant Cu2ZnSn(S,Se)4 (CZTSSe) solar cells is considerably lower than the Shockley–Queisser limit. One of the main reasons for this is the presence of deleterious cation disordering caused by SnZn antisite and 2CuZn+SnZn defect clusters, resulting in a short minority carrier lifetime and significant band tailing, leading to a large open‐circuit voltage deficit, and hence, low efficiency. In this study, Ga‐doping is used to increase the CZTSSe solar cell efficiency to as high as 12.3%, one of the highest for this type of cells. First‐principles calculations show that the preference of Ga3+ occupying Zn and Sn sites has a benign effect on suppressing the formation of the SnZn deep donor defects by upwardly shifting the Fermi level, which is further confirmed by deep‐level transient spectroscopy characterization. Besides, the Ga dopants can also form defect‐dopant clusters, such as GaZn+CuZn and GaZn+GaSn, which also have positive effects on suppressing the band‐tailing states. The defect engineering via Ga3+‐doping may suppress the band‐tailing defect with a decreased Urbach energy, elevate the minority carrier lifetime, and in the end, enhance the VOC from 473 to 515 mV. These results provide a new route to further increase CZTSSe‐based solar cell efficiency by defect engineering.

CsPbI3−xBrx‐based organic‐free perovskite has emerged as a superstar photovoltaic material not only because of its superior photoelectronic properties but also its outstanding thermal and chemical stability. Unfortunately, the significant energy loss resulting from its nonradiative recombination has become a major obstacle to further improvement of device performance. Here, a 2D/3D multidimensional structure formed spontaneously at room temperature is developed. The results reveal that the formed Ruddlesden–Popper 2D (n = 1) perovskite atop CsPbI3−xBrx plays an active role in mediating carrier transport, maintaining a long‐life charge separation state on the nanosecond time scale and promoting the efficiency of carrier injection into the hole transport layer, and thus enhances the hole extraction efficiency, which greatly reduces severe interfacial nonradiative charge recombination. In addition, the undercoordinated Pb2+ is effectively passivated, resulting in significantly reduced surface trap density and prolonged charge lifetime within the perovskite films. Consequently, the combination of the above increases the solar cell efficiency from 19.05% to 20.31%, with an open‐circuit voltage raised to 1.23 from 1.17 V, which corresponds to an energy loss reduction from 0.54 to 0.49 eV. Also, the optimized solar cells exhibit better long‐term and thermal stability.

Minimizing surface defect is vital to further improve power conversion efficiency (PCE) and stability of inorganic perovskite solar cells (PSCs). Herein, we designed a passivator trifluoroacetamidine (TFA) to suppress CsPbI 3À x Br x film defects. The amidine group of TFA can strongly chelate onto the perovskite surface to suppress the iodide vacancy, strengthened by additional hydrogen bonds. Moreover, three fluorine atoms allow strong intermolecular connection via intermolecular hydrogen bonds, thus constructing a robust shield against moisture. The TFA-treated PSCs exhibit remarkably suppressed recombination, yielding the record PCEs of 21.35 % and 17.21 % for 0.09 cm 2 and 1.0 cm 2 device areas, both of which are the highest for allinorganic PSCs so far. The device also achieves a PCE of 39.78 % under indoor illumination, the highest for allinorganic indoor photovoltaic devices. Furthermore, TFA greatly improves device ambient stability by preserving 93 % of the initial PCE after 960 h.

The narrow bandgap (≈1.2 eV) Pb-Sn alloyed perovskite solar cell is a promising bottom component cell for all-perovskite tandem devices that are expected to offer higher efficiency than the theoretical Shockley-Queisser limit of the single-junction solar cells. The density functional theory (DFT) study reveals that the Pb-Sn perovskite film with the (100) orientation would render significantly reduced trap density, which is a critical figure-of-merit for perovskite device performance. Alkyl diamine is therefore designed to first anchor onto the surface as a nucleation agent to modulate the Pb-Sn perovskite growth to proceed preferentially along with the (100) orientation. It is observed that the diamine cations not only effectively induced the crystal growth at the nucleation stage, but also remained on the crystal surface to eventually passivate the resultant perovskite film. As a result, the diamine-based films show (100) preferred orientation with superior optoelectronic properties, as predicted by the DFT investigation. Consequently, the champion power conversion efficiency of 20.03% is achieved, one of the highest for this type of device. These findings provide a practicable strategy to theoretically design surface nucleation to induce preferential growth of perovskite material for better optoelectronic performance.

Metal-halide perovskitoids with corner-, edge-, and face-sharing octahedra provide a fertile "playground" for structure modulation. With low defect density, low ion migration, and high intrinsic stability, two-dimensional (2D) perovskitoid single crystals are expected to be ideal materials for room-temperature semiconductor detectors (RTSDs) as high-energy radiation. However, there is no report yet on the use of 2D perovskitoid single crystals for X-ray detection, as well as on how the halide-modulated molecular assembly would affect their structure and properties. Herein, based on an amidino-based organic spacer, we successfully synthesized a novel family of centimeter-sized 2D perovskitoid single crystals, (3AP)PbX 4 (3AP = 3amidinopyridine, X = Cl, Br, and I). This is the first time that centimeter-sized 2D perovskitoid single crystals are demonstrated for X-ray photoresponse. Detailed investigations reveal a unique crystal packing with corner-sharing and edge-sharing octahedra of inorganic frameworks and 3AP cations lying between adjacent inorganic layers in a parallel and antisymmetric manner. Changing the halide from I to Br and Cl results in greater Pb−X−Pb angles and stronger hydrogen bonding in perovskitoids and therefore consequently a better elastic recovery under stress, a more efficient charge transport in the inorganic layer, and a lower ionic migration. By varying halide substitution, an efficient X-ray photoresponse is achieved with a sensitivity up to 791.8 μC Gy air −1 cm −2 for (3AP)PbCl 4 and a low detection limit of 1.54 μGy air s −1 . These results reveal that the large 2D perovskitoid single crystals provide a promising platform for high performance optoelectronics.

The photovoltaic performance of the kesterite Cu2ZnSn(S,Se)4 solar cells is still far below its predecessor CuInGaSe2. One major reason is its severe interface nonradiative recombination at the mismatched Cu2ZnSn(S,Se)4/CdS heterojunction interface, leading to a large open‐circuit voltage loss. Herein, a distinctive indium‐incorporation (DI) strategy is developed to deposit an In1−xCdxS buffer layer for optimizing the heterojunction interface. The results reveal that adopting this DI method can effectively inhibit the formation of an undesirable secondary phase, and indium can be more easily doped into the bulk lattice of CdS to form additional beneficial shallow donor InCd defects, which significantly improve the electrical properties of the CdS layer and the quality of the heterojunction interface. Besides, the energy band alignment is adjusted to facilitate the extraction and transfer of interfacial charges, and thus reducing the nonradiative charge recombination at the front Cu2ZnSn(S,Se)4/CdS heterojunction interface. Consequently, the combination of the above enhances the power conversion efficiency from 10.2% to 12.4%, one of the highest for this type of cells, which corresponds to an open‐circuit voltage deficit (Voc,def) reduction to as low as 0.54 V. The strategy provides a rational design for optimizing the heterojunction interface of Cu2ZnSn(S,Se)4 solar cells to reduce voltage loss and achieve high efficiency.