Growth Of Organic-inorganic Perovskite Single Crystal With Adjustable Band Gap And Its Photoelectric Properties

The organic-inorganic hybrid perovskite ABX3 has emerged as a desirable light-harvesting material due to its superior characteristics including high and broad absorption property,high electron mobility,long carrier lifetime and direct bandgap,etc.It has been one of the hot area of researches in photovoltaic and general optoelectronic applications.One of important research directions in perovskite field is to prepare and study the perovskite single-crystalline.There have been many reports about preparation and application of perovskite single-crystalline,but few of them relates to the hybrid perovskite single-crystalline.Instead,most of them are limited to the single metal or single halogen perovskite single-crystalline.Recently,many high efficiency perovskite solar cells employ the hybrid perovskite materials as the light absorption layer.Thus,the preparation of perovskite single crystal and investigation of its photoelectric property have become the best way to reveal the high photoelectric conversion efficiency of perovskite materials.In this paper,based on the characteristic of controllable chemical composition and structure of perovskite materials,we have prepared series of hybrid perovskite single crystals with fine controlled composition,absorption range and bandgap.And they have been applied to fabricate photodetectors,which show high work performance.The result demonstrates that the hybrid perovskite photodetectors possess huge competitive edge in the optoelectronic applications field.The innovative results of the subject are shown as follows:1.A series of perovskite MAPb(BrxI1-x)3(x =0～1)single crystals have been prepared using a strategy of inverse-temperature reactive crystallization.Considering the properties that halogen ions have different solubility in different solvent and different perovskite single crystal possess its optimized solvent,it is extremely difficult to obtain high quality single crystalline using single solvent.Therefore,we designed a straightforward route to grow composition-tuned dual-halide perovskite MAPb(BrxI1-x)3 single crystals by combining precursor solutions optimized individually for growing MAPbBr3 and MAPbI3 single crystals.The characterizations of EDS、XRD and Vis-NIR prove that by the currently developed method,it is indeed feasible to obtain dual-halide perovskite MAPb(BrxI1-x)3 single crytals with controlled ratio of Br,further to achieve the fine-tuned optical absorption range and bandgap.2.For the first time,by the strategy of inverse-temperature reaction crystallization,combined with the mixture of FAPbI3 and MAPbI3 precursors,we obtained a series of FAxMA1-xPbI3(x = 0～1)single crystals with fine-tuned bandgap.The characterizations of XRD、TGA and Vis-NIR prove that it is a practical way to get the FAxMA1-xPbI3 single crystals with fine-tuned bandgap by our developed method.This result could provide reference and inspiration for future study.3.The dual-halide perovskite MAPb(BrsI1-x)3 single crystals have been used to fabricate planar photodetectors.It is found that the MAPb(BrxI1-x)3 single crystal photodetectors with different compositions x exhibit the selective optimal response spectrum.The photodetector based on a Br-rich composition MAPb(Br0.78I0.22)3 single crystal exhibits excellent work performance.All the results could provide some new ideas and technological choices for future research of specific wavelength photodetectors.