Preparation And Photovoltaic Properties Of Sb₂S₃?Se? Thin Films

Sb₂S₃?Se?is an ideal absorber for high efficiency solar cells with the advantages of high absorption coefficient,tunable band gap,environmental friendliness and abundant raw material sources.Thus,it has a good application prospects in photovoltaic use.In recent years,researchers have made sufficient effort on Sb₂S₃?Se?solar cells.For the technical shortage,there is still a gap to commercial photovoltaic products,such as silicon solar cells.Now,improving Sb₂S₃?Se?films quality is the essential way to improve the performance to reach the theoretical photoelectric conversion efficient.In this work,we have reduced the defect density by improving crystal quality of Sb₂S₃?Se?film with the modified process and a post-treatment.We have carefully studied the effect of selenylation on the morphology,crystal structure as well as crystal defects for the films.And the photovoltaic performance of Sb₂S₃?Se?thin film solar cell has been significantly improved.The main content of this thesis consists of two parts as follow.?1?Firstly,we have prepared Sb₂S₃ thin films by vacuum thermal evaporation with a fast selenylation approach.It indicating that fast selenylation has improved the crystallinity property,moreover it has some good effect on suppressing of crystal defects.Meanwhile,fast selenylation is helpful to optimize the energy level matching and improve the carrier transport efficiency.When the selenization time was 12 min and the selenization temperature was 400 ^oC,the photoelectric conversion efficiency?PCE?of the device increased from 0.01%to 2.13%.?2?Secondly,we have prepared Sb₂S₃ thin films by spray pyrolysis in air.The crystallization quality of Sb₂S₃ films has also been improved by fast selenylation approach.According to Fick's second law,the diffusion process of selenization has been studied.And the effect of selenization on the crystal structure,band structure and carrier transport process has been discussed.By the process optimization,the open circuit voltage VOC and PCE of Sb₂S₃?Se?photovoltaic devices has reached 0.71 V and 3.18%respectively.This performance is much higher than the devices fabricated by vacuum method.We have employed an organic buffer layer to reduce and passivate macroscopic pore defect in the film surface.And then the carrier transport efficiency has been improved effectively,and the device PCE has been further improved to 4.57%.And,we have successfully fabricated a large-area?80×80 mm²?device with a 21 cm² active area based on spray pyrolysis and fast selenylation technology after the circuit and mask design.The large-area device has achieved a maximum PCE of 3.19%,indicating this technology has a good application prospect in photovoltaic fabrication.In summary,we have effectively improved the performance for both vacuum thermal evaporated and spray pyrolysis prepared Sb₂S₃?Se?photovoltaic devices with the fast selenylation approach and prepared a large-area and high-efficiency device.It is very important for low cost,high efficiency,large scale fabrication and commercial application of Sb₂S₃?Se?thin film solar cells.