透過在電洞傳輸層中引入近紅外光非富勒烯受體以實現對硫化鉛量子點本體異質接面太陽能電池的協同鈍化

Abstract

本論文探討在硫化鉛膠體量子點 (PbS CQD) 太陽能電池中，導入兩種結構相似的近紅外光 (NIR) 非富勒烯受體 (NFA) —BTPV-4F 與 BATPV-4F，並結合非富勒烯供體 PTB7-Th 及富勒烯受體PC71BM組成本體異質結型電洞傳輸層 (BHJ-HTL)。NFAs 除了能擴展太陽光譜的NIR吸收範圍，亦可形成三維電荷傳輸通道，提升裝置的光電流(JSC)。GIWAXS 與 AFM/KPFM 結果顯示，於 HTL 中引入 NFAs 並經由溶劑蒸氣退火 (SVA) 後處理，可有效縮短 π–π 堆疊距離並延長晶體干涉長度(CCL)，使 NFA 分子排列呈現長程有序的 face-on 堆疊，來縮短分子間電荷跳躍距離以促進電洞傳輸。此外，由X 射線光電子能譜 (XPS) 推測，PbS CQD 表面缺陷的鈍化主要來自於 Pb–S (BTPV-4F) 及 Pb–O ( BATPV-4F) 之間的相互作用。基態螢光光譜 (PL) 與飛秒瞬態吸收光譜 (fs-TA) 結果亦驗證NFAs 的導入可顯著提升 PbS CQD 激子解離並抑制非輻射複合，以達成 PbS/BHJ-HTL 界面鈍化，進而有效提升元件之開路電壓 (VOC) 與填充因子 (FF)。最終，採用 BTPV-4F NFA BHJ-HTL的 PbS CQD太陽能電池展現出高達 14.02 % 的光電轉換效率，亦具備優異的環境穩定性與熱穩定性。

This study investigates the bulk heterojunction (BHJ)-type hole-transporting layer (HTL) of lead sulfide colloidal quantum dot (PbS CQD) solar cells via incorporating two structurally similar near-infrared (NIR) non-fullerene acceptors (NFAs), BTPV-4F and BATPV-4F, blended with non-fullerene polymer donor PTB7-Th and fullerene acceptor PC71BM as hole-transporting materials (HTMs). In addition to broadening the NIR absorption range of the solar spectrum, NFAs could also construct three-dimensional charge transport channels that enhance the photocurrent (JSC) of the devices. Results from the Grazing-Incidence Wide-Angle X-ray Scattering (GIWAXS) and the Atomic Force Microscopy / Kelvin Probe Force Microscopy (AFM/KPFM) reveal that incorporating NFAs into the HTL, followed by the solvent vapor annealing (SVA) treatment, effectively reduces the π–π stacking distance and increases the crystal coherence length (CCL). SVA treatment promotes the NFA molecules’ long-range ordered face-on orientation, thereby shortening intermolecular charge hopping distances and facilitating hole transport. Moreover, we suggest that the passivation of surface defects on PbS CQDs is primarily achieved through Pb–S (with BTPV-4F) and Pb–O (with BATPV-4F) interactions through X-ray Photoelectron Spectroscopy (XPS) analysis. Steady-state photoluminescence (PL) spectrum and Femtosecond-Transient Absorption Spectroscopy (fs-TA) further confirm that the incorporation of NFAs significantly enhances exciton dissociation of PbS CQDs and suppresses non-radiative recombination, contributing to interfacial defect passivation at the PbS/BHJ-HTL interface. The above evidence shows noteworthy improvements in the open-circuit voltage (VOC) and fill factor (FF) of devices. As a result, the PbS CQD solar cell employing BTPV-4F NFA for BHJ-HTL achieves a high power conversion efficiency (PCE) of 14.02 %, along with excellent environmental and thermal stability.