鈣鈦礦太陽能電池（Perovskite solar cells, PSCs）憑藉其高光電轉換效率（Power conversion efficiency, PCE）與低成本製程，近年來受到廣泛關注。然而，傳統使用的疊層式三明治結構中，入射光在到達吸光層前，須依次通過玻璃基板、透明導電層及載子傳輸層，導致不可避免的光學損耗。背接觸式鈣鈦礦太陽能電池（Back-contact perovskite solar cells, BC-PSCs）將所有電極與載子傳輸層配置於吸光層下方，使鈣鈦礦層成為入光面，可有效降低光學損耗。
本研究提出以奈米壓印微影技術（Nanoimprint lithography, NIL）結合反應式離子蝕刻（Reactive ion etching, RIE）製程，製作亞微米等級 （Submircon scale）的蜂巢狀準多孔電極（Honeycomb quasi-porous electrode, HQPE），以縮小背接觸的電極寬度與間距，使其與鈣鈦礦層的載子擴散長度匹配，期望能提升載子收集效率。奈米壓印具備高解析度、低成本與高重現性，搭配自上而下的蝕刻策略能避免舉離不完全問題並確保背接觸電極結構的完整性。此外，採用 SU-8 有機絕緣層能有效隔絕上下電極，避免電極接觸造成電池短路。研究重點聚焦於壓印與蝕刻等製程參數的優化，並考量電子傳輸層品質會影響載子萃取，同時探討以濺鍍（Sputtering）與原子層沉積（Atomic layer deposition, ALD）兩種製程方式所製備氧化錫（SnO2）電子傳輸層，首先調控沉積參數來優化n-i-p三明治結構元件的光伏性能，再進一步應用至背接觸式鈣鈦礦太陽能電池。
研究結果顯示，本研究所建立之奈米壓印技術結合反應式離子蝕刻製程可成功製作背接觸式電極結構，展現出優異的製程穩定性與再現性，未來可在此基礎上進一步針對背接觸太陽能電池的結構設計、載子行為與光伏特性進行更深入的分析與研究。

Perovskite solar cells (PSCs) have garnered significant attention in recent years for their high power conversion efficiency (PCE) and cost-effective fabrication processes. However, in conventional sandwich-type architectures, incident light must traverse the glass substrate, transparent conductive oxide (TCO) layer, and charge transport layers before reaching the perovskite absorber, resulting in inevitable optical losses. Back-contact perovskite solar cells (BC-PSCs) address this issue by positioning all electrodes and charge transport layers beneath the perovskite layer, enabling direct illumination of the absorber and effectively minimizing optical loss. Despite this structural advantage, the PCE of BC-PSCs remains substantially lower than that of conventional devices. In most reported BC-PSCs, the BC-electrode linewidth and spacing are in the micrometer (μm) range—significantly larger than the carrier diffusion length in the perovskite layer—leading to pronounced carrier recombination and limiting device photovoltaic performance.
In this work, nanoimprint lithography (NIL) combined with a plasma etching process was employed to fabricate submicron-scale honeycomb quasi-porous electrodes (HQPEs) in the BC-PSCs for improved carrier collection efficiency. This top-down patterning strategy achieves highly uniform and reproducible BC-electrode, effectively mitigating lift-off failures, and maintaining the integrity of BC-electrode. The fabricated back-contact device achieved a PCE of 1.2%, preliminarily demonstrating the feasibility of the proposed fabrication process.

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