A novel convenient and efficient approach to produce CsSnI3 QDs through a one-pot synthesis is employed to largely enhance the PCE of lead-free perovskite solar cells (PVSCs). The CsSnI3 QD-based device has the maximum PCE of 5.03%, which is the highest performance for all-inorganic lead-free PVSCs reported so far.

Photodetectors with high photoelectronic gain generally require a high negative working voltage and a very low environment temperature. They also exhibit low response speed and narrow linear dynamic range (LDR). Here, an organic photodiode is demonstrated, which shows a large amount of photon to electron multiplication at room temperature with highest external quantum efficiency (EQE) from ultraviolet (UV) to near-infrared region of 5.02 × 10 % (29.55 A W ) under a very low positive voltage of 1.0 V, accompanied with a fast response speed and a high LDR from 10 to 10 mW cm . At a relatively high positive bias of 10 V, the EQE is up to 1.59 × 10 % (936.05 A W ). Inversely, no gain is found at negative bias. The gain behavior is exactly similar to a bipolar phototransistor, which is attributed to the photoinduced release of accumulated carriers. The devices at a low voltage exhibit a normalized detectivity (D*) over 10 Jones by actual measurements, which is about two or three order of magnitudes higher than that of the highest existing photodetectors. These pave a new way for realization of high sensitive detectors with fast response toward the single photon detection.

Interface engineering is very important to the high performance of organic optoelectronic devices that are commonly composed of multilayer thin solid films. Interfacial materials are particularly crucial for interface engineering, and a variety of materials have been employed at the interface to accomplish various different functions. This Review summarizes various materials for the interfaces and some of the latest progress in organic solar cells (OSCs) and organic photodetectors (OPDs).

The film quality of organometallic halide perovskite is very crucial to the performance of planar heterojunction solar cells. Previous methods have generally required a long-time and complex process to control the crystal growth for obtaining a compact and smooth perovskite film. Here, we demonstrate a novel method of growing the high-quality films via a simple and rapid process. Organic cations are used as additives in the solution of CH3NH3PbI3 (MAPbI3), which plays a key role in the film-forming process. These organic cations can enhance the film-forming ability and do not lead to a residue in the film end-product. On the basis of these characteristics, highly efficient perovskite solar cells with a simple planar heterojunction structure were achieved. Because the additives can simplify and accelerate the fabrication process and have no chance to induce any negative effect on the device, they will have a large potential in the production of various high-quality perovskite films and low-cost, large-scale, and high-performance devices.

Despite the rapid progress of the power conversion efficiency (PCE) of perovskite solar cells, the reproducibility, stability, and large‐scale production are major challenges. Here, we present a simple and quick solution‐depositing process to achieve high‐quality perovskite films by adding an insulating polymer of polyacrylonitrile (PAN) as a film‐forming additive into the CH3NH3PbI3 solution. With the CH3NH3PbI3:PAN films serving as an active layer, planar heterojunction perovskite solar cells show a PCE of 13.08 % at an area of 0.12 cm2 and 7.32 % at a large area of 1.0 cm2. The PCE loss is only about 40 % from the small‐area to larger‐area devices fabricated by using a solution‐based deposition process. The measurements were performed in air without any device encapsulation. We also used the conjugated polymer poly(3‐hexylthiophene) (P3HT) as the alternative for PAN. The device performance indicates that the conjugated polymer is unsuitable as the additive, which we attribute to the photo‐induced charge transfer between CH3NH3PbI3 and P3HT.