高性能金屬氧化物薄膜於高效率四接點鈣鈦礦/矽晶疊層型太陽能電池之應用

High Performance Metal Oxide Thin Film for Highly Efficient Four-terminal Perovskite/Silicon Tandem Solar cell

李沛寰(Pei-Huan Lee)

指導教授 ： 林唯芳

共同指導教授 ： 佳莉亞(Yulia Galagan)

國立臺灣大學/工學院/材料科學與工程學研究所/博士(2021年)

https://doi.org/10.6342/NTU202100817

摘要

開發鈣鈦礦/矽晶基疊層型太陽能電池是目前提升矽晶太陽能電池效率最有效的方法之一。本論文旨在開發具有成本效益、穩定及高性能的金屬氧化物電洞傳輸層、電子傳輸層以及透明電極之材料，藉此改善半透明鈣鈦礦太陽能電池的效率以及紅外光穿透度，並進一步應用於鈣鈦礦/矽晶疊層型太陽能電池中。
氧化鎳(NiOX)是用於鈣鈦礦太陽能電池中最具潛力的金屬氧化物電洞傳導材之一。我們開發了一種近紅外光輻射快速加熱法，成功將氧化鎳之熱退火時間從30分鐘縮短至1分鐘內。為進一步提升效率，我們透過鈷摻雜氧化鎳增加電洞萃取效率並減少電荷累積。此外，我們亦開發乳化膠束合成法，製備可低溫(<150 oC)製程之高結晶度氧化鎳奈米粒子，大幅改善鈣鈦礦太陽能電池的批次穩定性。而在電子傳導材部分，透過配位基置換有機分子於金屬氧化物奈米粒子表面，開發具功函數可調性和良好分散性的新型雙功能電子傳導材，而此配位基置換法可成功應用於SnO2, TiO2, ITO及CeO2¬¬各式奈米粒子，說明了其廣泛適用性。
儘管濺鍍之透明導電氧化物已被大量用於作為半透明鈣鈦礦太陽能電池之透明電極，在濺鍍的過程中，高能量濺射粒子會破壞底下的材料。為克服此問題，我們引入了先前所開發出的有機分子修飾之金屬氧化物奈米粒子作為保護層。此外，諸如氟摻雜的氧化錫(FTO)和銦摻雜的氧化錫(ITO)等商用之透明導電氧化物，因自由載子吸收導致紅外光波段的穿透度下降，而不適合應用於鈣鈦礦/矽晶疊層型太陽能電池。為解決此問題，我們以鈰摻雜之氧化銦(ICO)取代常見之ITO及FTO透明導電膜，藉此改善半透明鈣鈦礦太陽能電池之平均紅外光穿透度。
最後，我們引入光學及電學模擬技術，找出最佳的透明電極及抗反射層之厚度，以改善鈣鈦礦上電池之紅外光穿透度。根據模擬結果製作的半透明鈣鈦礦太陽能電池，其平均紅外光穿透度可提升至83.5%，最後四端點鈣鈦礦/矽晶太陽能電池之轉換效率能夠達到26.9%，超越單結矽晶太陽能電池之23%。本論文的研究成果在材料開發、元件製程以及光電性質的優化等三方面為鈣鈦礦/矽晶疊層型太陽能電池技術做出貢獻。

關鍵字

金屬氧化物 ； 近紅外光加熱 ； 溶液製程 ； 奈米粒子 ； 濺鍍 ； 鈰摻雜氧化銦 ； 半透明 ； 鈣鈦礦 ； 太陽能電池 ； 矽晶 ； 疊層

並列摘要

Development of perovskite/silicon tandem solar cell is one of the most effective way to further improve the power conversion efficiency (PCE) of silicon-based solar cell. To fabricate perovskite/silicon tandem solar cell, in this dissertation, we aim to develop cost-effective, stable, and high-performance metal oxide hole transport materials (HTM), electron transport materials (ETM) and transparent electrode (TE) for highly-efficient semi-transparent perovskite solar cell to be tandemed with commercial silicon solar cell.
Nickel oxide (NiOX) is one of the most promising metal oxide HTM for PVSCs. To shorten the process time of NiOX film, we develop a facile method to obtain high quality NiOx film by using near infrared (NIR) radiation. By optimizing NIR radiation parameter, the heating time could be significantly reduced from 30 min to 1 min. In addition, the NIR annealed cobalt-doped NiOx (NIR-Co:NiOX) was synthesized to replace pristine NIR-NiOx. The PCE of PVSCs fabricated from this new NiOx film can be improved due to the efficient hole extraction and less charge accumulation. In addition to the long heating time, the process temperature of NiOX film should also be reduced. Herein, we demonstrate a facile emulsion process (EP) to synthesize highly crystalline, low temperature (<150oC) and solution processable NiOx nanoparticles (NPs) as a hole transport layer for the PVSCs. The quality of the EP-NiOX film shows a good batch-to-batch uniformity, resulting in an excellent reproducibility of PVSCs. For the metal oxide ETM, we successfully developed a general ligand exchange method to prepare a novel dual function organic-molecule-capped metal oxide NPs with low-work-function tunability and excellent dispersibility. The ligand exchange method can be applied to SnO2, TiO2, ITO, and CeO2 NPs, demonstrating its broad applicability.
To fabricate semi-transparent perovskite solar cells (ST-PVSCs) with high average near-infrared transmittance (AVT), the sputtered transparent conductive oxides (TCO) is applied for being TE. However, the attack of highly energetic ions during the sputter deposition tends to damage the underlaying materials. To overcome this issue, we introduced the ETL layer developed in above to protect the underlaying layer. Moreover, the commonly used commercial TCO such as fluorine-doped tin oxide (FTO) and indium doped tin oxide (ITO) suffer from free carrier absorption (FCA) in the NIR region, which is not suitable for the perovskite/silicon tandem solar cell. Therefore, we introduced a cerium doped indium oxide (ICO) with high AVT to replace the ITO and FTO, leading to the significant improvement in the ANT of ST-PVSCs.
The ST-PVSCs developed from above was applied as the top cell to tandem with silicon bottom cell. Although, we have solved the problem of FCA effect in TCO, the film reflection still reduces the ANT of ST-PVSCs. The optical and electrical modeling was used to simulate the optimized thickness of ICO electrode and LiF anti-reflection (AR) layer for further improving ANT. After the optimization, the ANT of ST-PVSCs can be improved to 83.5%. Finally, the 4-terminal perovskite/silicon tandem cell exhibits a PCE of 26.9%, which surpasses the PCE of 23% of single junction silicon solar cell. The scientific results of this dissertation will contribute to the advancement of perovskite/silicon tandem solar cell technology in the aspects of the material development, optical-electrical property management and device processing.

並列關鍵字

metal oxide ； near infrared ； solution process ； nanoparticle ； sputtering ； cerium doped indium oxide ； semi-transparent ； perovskite ； solar cell ； silicon ； tandem

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