線型與星型鈍化劑對鹵化鈰鈣鈦礦之協同鈍化效應

Abstract

本研究成功合成一種具有鉛取代潛力、空氣穩定性佳，且具電化學耐久性的鈰基鹵化物鈣鈦礦材料，其組成為CC/6mna/(FA0.8MA0.2)3Ce1-xGexI6，為提升薄膜品質與光電性能，本研究引入兩種三苯甲烷類有機染料—結晶紫（CV）與甲基綠（MG）—作為路易士鹼表面鈍化劑。兩者皆為副玫瑰苯胺（pararosaniline）衍生結構染料，具備良好的共軛性，可與 Ce3+離子形成穩定配位，有效提升鈣鈦礦薄膜的表面穩定性。此鈣鈦礦薄膜可直接用作染料敏化太陽能電池對電極材料，為低成本且具潛力的電催化材料候選者。本研究採用兩階段乾燥與退火製程（150 °C 乾燥 2 小時，後續於 200 °C 快速退火 1 分鐘），並可在高濕環境下（相對濕度>75%）穩定製備高品質薄膜。透過掃描式電子顯微鏡（SEM）、X 光光電子能譜（XPS）、粉末 X 光繞射（PXRD）、紫外光電子能譜（UPS）及電化學阻抗分析（EIS）等技術進行系統性結構與電性分析。結果顯示，CV 鈍化薄膜具有緻密片狀形貌、較強的 Ce–I 鍵結與更佳能階排列，對應元件效率可達 9.26%，優於 MG 薄膜之非晶相結構的電性表現。進一步透過雙鈍化劑策略（CV + 4,4'-Bpy）可進一步改善表面配位強度、降低 Ce–O 含量與表面缺陷，並明顯提升開路電壓與短路電流，使 DSSC 效率達到10.85%，超越傳統白金對電極所達成之效能。EIS 顯示 CV + 4,4'-Bpy 組合具最低電荷轉移電阻（Rct = 5.11 Ω cm2），具有優異界面導電性。本研究顯示，藉由分子結構設計與鈍化策略，鈰基鈣鈦礦電極不僅具鉛替代潛力，亦可望應用於高效、環境友善之太陽能與電化學系統。

The Ce-based perovskite electrode, stable under oxygen-rich conditions, consists of carbon cloth (CC)/6-mercaptonicotinic acid (6mna)/(FA0.8MA0.2)3Ce1-xGexI6 and is passivated with two triphenylmethane-derived organic dyes, crystal violet (CV) and methyl green (MG). These cationic dyes are structural derivatives of pararosaniline, featuring conjugated aromatic backbones and electron-donating amino groups, which facilitate Lewis base coordination with Ce³⁺ and enhance surface stabilization. The resulting perovskite electrodes were employed as electrocatalytic counter electrodes in dye-sensitized solar cells (DSSCs), where they effectively improved device performance by enhancing interfacial stability and catalytic activity. The perovskite thin films were fabricated via a two-stage drying process under ambient air with high humidity, and characterized using SEM, XPS, PXRD, UPS, and EIS techniques. Results showed that CV-passivated films exhibited dense, flake-like morphologies and improved Ce–I bonding, leading to better photovoltaic performance than MG-passivated films. Moreover, the dual-passivation strategy with CV + 4,4'-Bpy significantly enhanced interfacial coordination, reduced Ce–O content, and improved the energy level alignment, resulting in the highest cell efficiency of 10.85%, exceeding that of the traditional Pt-based counter electrode. Electrochemical impedance spectroscopy confirmed that the lowest charge transfer resistance (Rct = 5.11 Ω cm2) was achieved with CV + 4,4'-Bpy, indicating superior interfacial conductivity despite its limited bulk crystallinity. These findings demonstrate that Ce-based halide perovskites, when properly passivated with suitable Lewis-base additives, can serve as promising and sustainable alternatives for electrochemical and photovoltaic applications.