Yanqiang Hu

Air-stable CsPb1−xBixBr3 (0 ≤ x ≪ 1) perovskite crystals: optoelectronic and photostriction properties

The growth of single crystals allows a more accurate and reliable study of the intrinsic electrical and optical properties of halide perovskite materials. However, all-inorganic halide perovskite single crystals are difficult to prepare due to the poor solubility of the reactant precursors. In this paper, we report a series of air-stable Cs-based halide perovskite single crystals, CsPbBr3 and CsPb1−xBixBr3 (x ≪ 1), prepared via a modified antisolvent vapour-assisted crystallization method. The Cs-based halide perovskites exhibited low trap density and high carrier mobility that are comparable to those of organic–inorganic hybrid halide perovskite materials. Most importantly, the Bi-doped CsPb1−xBixBr3 perovskites also indicated excellent light absorption (covering the entire visible wavelength) and photostriction (effective photostriction of about 8 × 10−4) performances, which greatly expands the optoelectronic and optomechanical applications of these inorganic halide perovskite materials.

Recent Advances in One-Dimensional Halide Perovskites for Optoelectronic Applications

Metal-halide perovskites have emerged as efficient, low-cost energy materials owing to their remarkable optoelectronic properties. In particular, the dimensionality and morphology of crystallites may have a striking influence on their chemical and physical properties and therefore affect their optoelectronic applications. One-dimensional halide perovskites have superior carrier transportation in one dimension, high crystalline quality, and consequently, high quantum efficiencies and long carrier diffusion lengths, which are important for the performance of perovskite-based nanoscale optoelectronic and photonic devices. In this review, we highlight recent advances in the synthesis of one-dimensional halide perovskites and their unique properties as well as their novel optoelectronic applications. This review aims to provide an overview of the achievements in synthesis techniques and nanoscale optoelectronic applications based on one-dimensional perovskite nanocrystals.

Improved performance and stability of perovskite solar cells by incorporating gamma-aminobutyric acid in CH3NH3PbI3

Organic–inorganic hybrid perovskites have attracted enormous attention due to their remarkable properties for high-efficiency solar cells in recent years. However, controlling the morphology of perovskite films is still a challenge using a solution synthesis method. Perovskite films with incomplete coverage are inevitable and this significantly limits the device photoelectric performance and long-term stability. In this work, we have combined gamma-aminobutyric acid iodide (GABAI) and CH3NH3I (MAI) as a mixed amine source in a precursor solution to fabricate a mixed-cation perovskite (GABA)xMA1−xPbI3. As a result, high quality (GABA)xMA1−xPbI3 crystals were synthesized and showed better pore-filling and more complete contact with the TiO2 scaffold, enhancing the power conversion efficiency from 15.08 to 18.31% with respect to the controlled MAPbI3 solar cells. Importantly, the devices that contained GABA+ also showed much higher stability when compared to the reference MAPbI3 devices. This new chemical modification design, using bifunctional mixed cations in organic–inorganic hybrid perovskites, provides an efficient approach for improving both the performance and stability simultaneously.

Highly efficient flexible solar cells based on a room-temperature processed inorganic perovskite

All-inorganic perovskite cesium lead triiodine (CsPbI3) is emerging as a promising thermally stable light absorber in flexible optoelectronic devices. However, the photoactive α-CsPbI3 only exists at a temperature higher than 310 °C and rapidly degrades to the undesired δ-CsPbI3 at room temperature. Here, a vacuum-assisted drying process is first developed to fabricate all-inorganic perovskite thin films at room temperature. The film morphology and photoelectric properties as well as the long-time stability are significantly improved compared to those of the reference film fabricated with annealing process. The flexible solar cells based on such room temperature processed films demonstrate a high power conversion efficiency of 11.47% with a small hysteresis. Moreover, the champion flexible cell also exhibits high air-stability and excellent flexibility. These results offer a new pathway for developing high-performance and cost-effective flexible optoelectronic devices.