Recent Advances in Halide Perovskite Single‐Crystal Thin Films: Fabrication Methods and Optoelectronic Applications

Abstract

Metal‐halide perovskites have aroused intense interest in the scientific community by virtue of their numerous remarkable optoelectronic properties, which render them promising candidates for applications in various optoelectronic fields, such as solar cells, light‐emitting diodes, photodetectors, and lasers. Compared with perovskite polycrystalline films and nanocrystals, grain‐boundary‐free single‐crystal perovskites possess lower trap‐state densities, higher carrier mobilities, and longer diffusion lengths, which are supposed to deliver superior optoelectronic performance. However, the thickness (a few millimeters) of typical bulk single‐crystal perovskites are much greater than their carrier diffusion length (e.g., MAPbI3 SC, ≈175 µm), which results in severe charge accumulation and significantly hinders their development. To this end, fabricating single‐crystal thin films is of great importance for further exploring the potential of single‐crystal perovskites in various applications. In this paper, the rapid and prosperous developments in the fabrication methods of perovskite single‐crystal thin films are systematically summarized and recent encouraging progress in their physical and chemical properties as well as the optoelectronic applications (solar cells, photodetectors, and light‐emitting diodes) of single‐crystal thin films are reviewed. Finally, the challenges and a brief outlook for further improving the quality of perovskite single‐crystal thin films and optimizing the device design are highlighted.

Enhanced On–Off Ratio Photodetectors Based on Lead‐Free Cs3Bi2I9 Single Crystal Thin Films

“…These disharmonious characteristics as a result triggered severe charge recombination, thereby significantly hindering it from high performance optoelectronic applications. To solve this obstacle, fabricating single crystal thin film (SCTF) has been proposed as an effective strategy, since it can inherit almost all the superior photoelectrical properties from bulk single crystal and more importantly possess a reduced thickness (down to several micrometers) 6–8. Profiting from the great advance achieved in SCTF fabrication method, organic–inorganic lead halide perovskite (e.g., MAPbX 3 ) SCTF has recently become a front runner in photodetector field 9–12.…”

“…However, the halide migration issue has resulted in high dark current ( J dark ), and further unsatisfactorily limited the dynamic range of the detector as well as increased noise levels,13–15 thus deteriorating the on/off ratio ( J on / J off ), which is a critical parameter evaluating the device signal‐to‐noise ratio. Furthermore, easy volatilization of organic component in hybrid perovskites as well as the toxicity of lead are still two major issues limiting its future large‐scale market entry 8,15,16…”

“…as an effective strategy, since it can inherit almost all the superior photoelectrical properties from bulk single crystal and more importantly possess a reduced thick ness (down to several micrometers). [6][7][8] Profiting from the great advance achieved in SCTF fabrication method, organic-inor ganic lead halide perovskite (e.g., MAPbX 3 ) SCTF has recently become a front runner in photodetector field. [9][10][11][12] The photo detectors based on organic-inorganic halide perovskite deliver a glorious photo response typically with high photocurrent (J ph ).…”

“…Furthermore, easy volatilization of organic component in hybrid perovskites as well as the toxicity of lead are still two major issues limiting its future largescale market entry. [8,15,16] In the context of the search for effi cient leadfree perovskite materials, Bibased perovskites have gained great attention in terms of the low toxicity, high chemical stability. [17][18][19][20][21][22] Very recently, bismuthbased hybrid perovskite single crystals have been synthesized and reported, eg.…”

The Rise of Textured Perovskite Morphology: Revolutionizing the Pathway toward High‐Performance Optoelectronic Devices

“…owing to fascinating properties such as a tunable bandgap, high absorption coefficient, long carrier diffusion length, and simple solution processability. [7][8][9] In particular, extraordinary success has been achieved with both PSCs and perovskite-based LEDs (P-LEDs). For instance, the best-performing PSC has a certified record photon-to-current efficiency (PCE) of 25.2%, [10] which is already higher than other commercial thin film photovoltaic technologies.…”