常壓介電質放電噴射電漿表面改質奈米銀線電極n-i-p鈣鈦礦太陽能電池製程開發

Abstract

此研究為了達到全溶液製備正規結構鈣鈦礦太陽能電池，我們以空氣為載流氣體之噴閥式塗佈奈米銀線取代真空蒸鍍銀薄膜作為正規結構太陽能電池之上電極。由於奈米銀線在製備的過程中會加入聚乙烯吡咯烷酮(N-vinylpyrrolidone, PVP)保護劑幫助奈米銀線成長，所以市售的奈米銀線通常都會殘留一層聚乙烯吡咯烷酮在奈米銀線表面上，而此種化學物質除了會使奈米銀線彼此之間的傳導率降低之外，也會使奈米銀線與下層的電洞傳輸層之間的介面接觸變差，進而導致奈米銀線與電洞傳輸層的介面有電洞萃取能障(Hole extraction barrier)，而使正結構太陽能電池的整體元件特性下降。 為了減少聚乙烯吡咯烷酮對太陽能電池元件特性的影響，在製備完正規結構太陽能電池並且噴塗完奈米銀線後，我們用低溫(<40°C)常壓介電質放電噴射電漿分別以3、2、1與0.5 cm/s的掃描速率對奈米銀線進行表面改質。經由電性分析發現最佳掃描速率為0.5 cm/s，在此掃描速率下，元件的能量轉換效率達13.00%，填充因子為61.74%，相比於未經常壓介電質放電噴射電漿處理之元件的能量轉換效率只有9.10%，填充因子則為44.07%，由此可見經由常壓介電質放電噴射電漿處理過後的元件之性能有明顯的上升。最主要的原因為奈米銀線經過常壓介電質放電噴射電漿處理過後，在銀線表面的聚乙烯吡咯烷酮被移除，改善了奈米銀線之間與奈米銀線與電洞傳輸層之間的介面接觸，而提高了太陽能電池的元件特性。藉由片電阻量測、X射線能譜分析、水接觸角量測與電化學阻抗分析的結果都指出常壓介電質放電噴射電漿處理過後確實能夠移除聚乙烯吡咯烷酮，改善元件效率。

In this study, in order to achieve fully-solution processed n-i-p structure perovskite solar cells (PSCs), we use jet-sprayed AgNWs to take over from vacuum-deposited Ag film as the top electrodes of n-i-p PSCs. A layer of polyvinylpyrrolidone (PVP) covers AgNWs because of the addition of PVP during the growth process of AgNWs. This PVP degenerates not only the conductivity of AgNWs layer but also the contact among AgNWs and between AgNWs and the spiro-OMeTAD HTL. PVP also becomes charge extraction barrier when used as an electrode of a PSC. In order to reduce the influence of the PVP on the performance of the PSCs, low-temperature (<40°C) atmospheric-pressure dielectric-barrier-discharge-jet (DBDjet) is used to post-treat AgNWs at scan rate 3, 2, 1, 0.5 cm/s after completing the fabrication of n-i-p PSCs. With the DBDjet treatment at scan rate of 0.5 cm/s, the cell exhibits a photoelectric conversion efficiency (PCE) of 13.00% and fill factor (F.F.) of 61.74%. Compared with the cells without DBDjet treatment (PCE of 9.10% and F.F. of 44.07%), the performance is greatly improved. DBDjet plasma treatment removes PVP, improving the interfacial contacts among AgNWs and between AgNWs layer and hole transport layer; this in turn increases the cell efficiency. Sheet resistance measurement, X-ray photoelectron spectroscopy, water contact angle measurement, and electrochemical impedance spectroscopy all show evidence about the removal of PVP layer by the DBDjet plasma treatment