連續波雷射技術焊接奈米銀線薄膜應用於提升鈣鈦礦太陽能電池之效能

Abstract

隨著光伏科技的發展及光電產業的興起，人們大量使用觸控面板、穿戴裝置及智慧顯示器等光電產品，使得透明光電材料受到重視；其中作為透明導電薄膜(transparent conductive film, TCF)，奈米銀線具有高導電度、高穿透率及可彎曲性等特性而具有極高的潛力取代傳統的透明氧化物薄膜(transparent conductive oxide, TCO)，將奈米銀線作為鈣鈦礦太陽能電池的前電極是其重要的應用之一，而鈣鈦礦太陽能電池是一種新型太陽能電池，具有光電轉換效率高、製造成本低等優點。 本實驗透過真空抽氣法的方式將奈米銀線沉積於玻璃以及可撓性基材上，並利用自架532 nm波長的連續波雷射焊接奈米銀線薄膜，在不影響穿透率的情況下有效的降低奈米銀線之間的接觸電阻，使得薄膜導電性增加，最終以玻璃為基材的奈米銀線薄膜片電阻值從45.82 ohm/sq降至10.97 ohm/sq，得到76.06%的片電阻下降百分率後仍然保持89%的穿透率。接著，我們利用大氣電漿(atmospheric pressure plasma jet, APPJ)系統將氧化鋅摻雜(GZO)沉積於奈米銀線導電薄膜上，以抑止當使用奈米銀線薄膜作為鈣鈦礦太陽能電池電極時銀離子躍遷至鈣鈦礦層與碘離子反應而生成的不導電物質—碘化銀，透過改變電漿頭掃描速度來調整GZO厚度，最終在311 nm的GZO厚度下成功製備出有效的元件。 最後，我們將經雷射加工處理的奈米銀線薄膜作為前電極，配合GZO保護層製備出平均8.37%、最高9.24%光電轉換效率的鈣鈦礦太陽能電池。與未加入雷射加工的奈米銀線鈣鈦礦太陽能電池進行比較後，串聯電阻的下降和並聯電阻的提高使填充因子提高了8.92%，而由於改善了薄膜的導電性又同時降低了粗糙度，開路電壓和短路電流的乘積也獲得了3.34%的提升，實現出一種快速、製作成本低且有效率的方式來提升光伏電池性質。

With the development and rise of photovoltaic technology and the optoelectronics industry, there is a substantial usage of optoelectronic products such as touch panels, wearable devices, and smart displays. As a result, transparent conductive films (TCF) have gained significant importance. Among these, silver nanowires are highly promising due to their high conductivity, transparency, and flexibility, making them a potential replacement for traditional transparent conductive oxide (TCO) films. One of the important applications is to be the front electrode of perovskite solar cells (PVSCs). Perovskite solar cells have attracted many researchers effort in recent years, which showed a high photo-electric conversion efficiency (PCE) and low cost of fabrication process. In this experiment, silver nanowires were deposited on glass and flexible substrates using a vacuum filtration method. Subsequently, a continuous wave laser at a wavelength of 532 nm was used to nano-weld the silver nanowire films. This process effectively reduced the contact resistance between the silver nanowires without compromising transparency, resulting in an increase in electric conductivity. The sheet resistance of the silver nanowire film on a glass substrate was reduced from 45.82 ohms/square to 10.97 ohms/square, achieving a relative 76.06% reduction in sheet resistance while maintaining the same transparency of 89% (at 550 nm). Furthermore, an atmospheric pressure plasma jet (APPJ) system was employed to deposit gallium-doped zinc oxide (GZO) on the substrate with the silver nanowire conductive film. The purpose of GZO film is to inhibit the formation of non-conductive silver iodide resulting from the migration of silver ions to the perovskite layer when using the silver nanowire film as an electrode in perovskite solar cells. By adjusting the plasma head scanning speed, the thickness of the GZO layer was well controlled, and the thickness of 311 nm was chosen to be the barrier between silver nanowires and perovskite layer. Finally, the laser-processed silver nanowire film was used as the front electrode, along with the GZO protective layer, to fabricate perovskite solar cells with an average photovoltaic conversion efficiency of 8.37% and a maximum of 9.24%. Compared to perovskite solar cells without laser processing, the decrease in series resistance and the increase in shunt resistance led to relative 8.92% improvement in the fill factor. Additionally, due to the enhanced film conductivity and decreased roughness of silver nanowires film, the product of open-circuit voltage and short-circuit current also get a 3.34% increase, demonstrating a rapid, cost-effective, and efficient approach for photovoltaic cell production.