現今太陽能電池主要是由三層結構所構成,中間層多為單晶矽當作吸收層,再來會在正反面長一層Amorphous silicon當作鈍化層,增加載子飄移長度,最後分別在正反面再長一層高參雜P/N Silicon當作電子電洞選擇層,有了這層可以使載子減少複合機率。
近年受到高度關注的鈣鈦礦太陽能電池,其材料是由AX+BX_2=ABX_3所組成,特性擁有極佳的吸光效率以及載子飄移長度。而研究發現透過AX/BX_2的不同比例(缺陷,自參雜)、退火溫度可任意改質鈣鈦礦形成P、I、N type。我們希望透過這樣的特性,讓鈣鈦礦拿來當作電子電洞選擇層,其相較於利用矽的高參雜,擁有低溫低成本的優勢,且分別替換A、B、X亦可調配功函數,擁有很大的可調性,在未來太陽能電池的應用上有很大潛能。
而本實驗首先透過蝕刻的粗糙度及原生氧化層的親水性的特性克服鈣鈦礦在矽基板上成的問題,但考量到蝕刻會增加表面缺陷以及原生氧化層難以精準控制,最後我們採用蒸鍍MoO_3的方式當作基底。而雖然克服了鈣鈦礦成膜的問題,但鈣鈦礦(MAPbI_3)中內含(I)無法像其他有機材料可以直接與銀電極接觸,我們一樣用MoO_3當作中間層隔絕,由此建立我們的元件架構。
首先我們例用鈣鈦礦自參雜的特性,調配Ratio(PbI_2/MAI) =1、0.9、0.8,溶劑為DMF調配30w%的溶液。從電性方面發現，在Ratio(PbI_2/MAI) =0.8時F.F從62.07%提升至73.64%獲得大幅改善使元件光電轉換效率最高可達到11.23%。而利用AgI doping的方式改質鈣鈦礦,在濃度為AgI 1w%。從SEM下可以看到結晶顆粒變大使得缺陷減少,Jsc提升1mA,且F.F大幅改善10%使元件效率從9.44提升到11.42%。

Today's solar cells are mainly composed of a three-layer structure. The middle layer is mostly a single crystal germanium as an absorption layer, and then a layer of Amorphous silicon is used as a passivation layer on the front and back sides to increase the carrier drift length, and finally on the front and back sides respectively. A layer of high-doping P/N Silicon is used as the electron hole selection layer. This layer can reduce the carrier's probability of compounding.
In recent years, the perovskite solar cells, which are highly concerned, are composed of AX+BX_2=ABX_3, which has excellent light absorption efficiency and carrier drift length. The study found that through the different proportions of AX/ BX_2 (defects, self-doping), annealing temperature can be modified to form P, I, N type. We hope that through this kind of characteristics, perovskite can be used as an electron hole selection layer. Compared with the high impurity of using strontium, it has the advantages of low temperature and low cost, and can be replaced by replacing A, B and X respectively. The work function has great adjustability and has great potential in the future application of solar cells.
In this experiment, the problem of perovskite on the ruthenium substrate is overcome by the roughness of the etch and the hydrophilicity of the native oxide layer. However, it is considered that the etching will increase the surface defects and the primary oxide layer is difficult to control accurately. Finally, we use steaming. The method of plating MoO_3 is used as a substrate. Although the problem of perovskite film formation is overcome, the inclusion of I in perovskite (MAPbI_3) cannot be directly contacted with the silver electrode like other organic materials, and we use MoO_3 as the intermediate layer to isolate it. Our component architecture.
First, we used the characteristics of perovskite self-doping, and formulated Ratio (PbI_2/MAI) = 1, 0.9, 0.8, and the solvent was DMF to prepare 30w% solution. From the electrical point of view, F F increased from 62.07% to 73.64% when Ratio (PbI_2/MAI) = 0.8, which greatly improved the photoelectric conversion efficiency of the component up to 11.23%. The AgI doping method was used to modify the perovskite at a concentration of AgI 1w%. It can be seen from the SEM that the crystal particles become large to reduce defects, Jsc is increased by 1 mA, and F.F is greatly improved by 10% to increase the element efficiency from 9.44% to 11.42%.

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