高分子電解質電洞傳輸層對鈣鈦礦太陽能電池之影響

Abstract

吸光層與電洞傳輸層之間的界面不僅決定了能帶匹配和電荷傳輸的問題，還影響了鈣鈦礦的生長，因此選擇合適的電洞傳輸層有其必要性。本篇主要透過電洞傳輸層改質來提高 p-i-n 結構鈣鈦礦太陽能電池之效率，首先將 P3CT 與鹼金屬之合成取代傳統 PEDOT：PSS 作為電洞傳輸層，分為四種材料：P3CT-Na、P3CT-K、P3CT-Cs、P3CT-Rb，再分別以厚度 ( thickness ) 、溶液配置時間 ( aging time )、退火溫度 ( annealing temperature ) 三種條件做元件效率最佳化之分析，並透過 X射線繞射分析儀 (XRD) 及原子力顯微鏡 (AFM) 觀察不同退火溫度條件下薄膜晶體結構與形貌之變化，而以 P3CT-Na 做為電洞傳輸層比 PEDOT：PSS 最高可提升百分之四十的效率，並在 P3CT-Na與 P3CT-K 元件可達到正掃 17%、反掃 18% 的效率。

The interface between the perovskite film and the hole transport layer (HTL) not only determines band gap alignment and the hole transportation but also affects the growth of perovskite crystallites. Therefore, it is necessary to choose a suitable HTL. This thesis improved the power conversion efficiencies (PCEs) of the p-i-n structure perovskite solar cells (PSCs) through the modification of the hole transport layer. The PEDOT: PSS was replaced by the polyelectrolyte poly[3-(4-carboxybutyl)thiophene-2,5-diyl] (P3CT)-alkali metal. Four kinds of polyelectrolytes were synthesized: P3CT-Na, P3CT-K, P3CT-Cs and P3CT-Rb. The influence of the polyelectrolyte thickness, aging time and annealing temperature on the device performance were investigated. X-ray diffraction patterns and atomic force images were recorded to understand the changes in the film crystallinity and morphology. The device using P3CT-Na delivered superior device performance (40% increase) comparing with the performance of the device using PEDOT:PSS. The PCE values of 17% in forward scan and 18% in backward scan were obtained for the devices using P3CT-Na and P3CT-K.