應用於太陽能電池與發光二極體的近紅外染料

Abstract

本論文旨在探討將近紅外染料整合至鈣鈦礦太陽能電池與有機發光二極管的可行性。首先，我們開發了含硒的鄰位苯二吡咯（ortho-benzodipyrrole）基染料 CB-2Se（能隙 1.35 eV），並與 PCBM 組成本體異質結（bulk-heterojunction）層。透過去除 Tz 基團，CB-2Se 能有效抑制自聚集，進而提升其與 PCBM 的相容性。採用 CB-2Se:PCBM 的鈣鈦礦太陽能電池展現了 25.18% 的光電轉換效率，不僅優於僅含 PCBM（24.35%）及 PCBM:Y6-16（24.49%）的對照器件，亦具有優秀的長期穩定性：在 1000 小時後仍能保留 88% 的初始效率。飛秒瞬態吸收光譜進一步證實了 PCBM/CB-2Se 界面上在 200 fs 以內即完成極快速的激子分離，並首次觀察到電洞由 CB-2Se 回傳至鈣鈦礦層的過程。 在 OLED 製作方面，我們透過轉印技術，將特定的近紅外（NIR）螢光染料 BTP-eC9 轉印至一層鉑(II)錯合物薄膜上。該 Pt(II) 錯合物初始發射約在 740 nm，屬於深紅磷光；BTP-eC9 則在波長大於 900 nm 的範圍內產生螢光。在此雙層結構中，Pt(II) 錯合物之三重態能量可透過三重態-單重態能量轉移傳遞至 BTP-eC9，進而產生約 925 nm 的超螢光（hyperfluorescence），其外部量子效率高達 2.24%，最大輻射亮度可達 39.97 W sr⁻¹ m⁻²。此外，我們亦成功將此方法拓展至 BTPV-eC9，獲得 1022 nm 的發光，展現了超螢光 OLEDs 在近紅外領域的廣泛應用潛力。

In this work, we explore the integration of near-infrared (NIR) dyes into both perovskite solar cells (PSCs) and organic light-emitting diodes (OLEDs). First, we developed a selenium-incorporated ortho-benzodipyrrole-based dye, CB-2Se, with a bandgap of 1.35 eV to form a bulk-heterojunction layer alongside PCBM in PSCs. By removing the Tz unit, CB-2Se effectively suppresses self-aggregation, thereby improving compatibility with PCBM. The CB-2Se:PCBM-based PSC delivered a remarkable power conversion efficiency (PCE) of 25.18%, outperforming both the PCBM-only (24.35%) and the PCBM:Y6-16 (24.49%) reference devices, while also exhibiting enhanced long-term stability (retaining 88% of its initial efficiency after 1000 hours). Femtosecond transient absorption spectroscopy revealed ultrafast exciton separation at the PCBM/CB-2Se interface (within 200 fs) and, for the first time, a back-transfer of holes from CB-2Se to the perovskite layer. Meanwhile, using a transfer printing technique, we imprinted a designated NIR fluorescent dye (BTP-eC9) onto a thin layer of Pt(II) complex for OLEDs. The Pt(II) complex initially emits deep-red phosphorescence at ~740 nm, while the BTP-eC9 dye fluoresces at >900 nm. Under this imprinted bilayer architecture, Pt(II) phosphorescence undergoes triplet-to-singlet energy transfer to BTP-eC9, yielding strong hyperfluorescence at ~925 nm with an external quantum efficiency of 2.24% and a maximum radiance of 39.97 W sr⁻¹ m⁻². This approach was also successfully extended to BTPV-eC9, reaching 1022 nm emission, highlighting the broad potential of hyperfluorescent OLEDs in the NIR region.