硒化鉛合成與薄膜改質之光伏電池應用研究

Abstract

本篇論文利用溶液相法，成功合成不同第一激發吸收波長的PbSe量子點，並利用化學處理法將PbSe薄膜浸泡在butylamine之 acetonitrile溶液中去除油酸，再將此薄膜於氮氣下燒結，最後旋轉塗佈上PCBM:P3HT薄膜，應用於太陽能電池。實驗中，發現改質液濃度、浸泡時間及燒結溫度和時間，會影響太陽能光電轉換效率。將製備好的PbSe薄膜於氮氣下燒結，藉由FTIR和TGA的析，可得知一定的燒結溫度可去除油酸官能基，並經XRD鑑定，發現燒結會使粒子成長並增加結晶性。之後將改質後的PbSe薄膜進行FTIR測量，發現隨改質液濃度或浸泡時間增加油酸去除量會提高，並經SEM觀測發現薄膜改質後會出現裂縫，這些裂縫隨著改質液濃度增加而變大，表示因油酸的去除造成粒子之間距離縮短。再將此薄膜於氮氣下燒結，藉由FTIR的鑑定發現在一定溫度下，燒結能夠增加油酸去除量。最後在此薄膜上旋轉塗佈PCBM:P3HT薄膜，藉Near IR-UV-Visible吸收光譜儀的測量，發現PbSe薄膜能增加PCBM:P3HT薄膜可見光至紅外光區的吸收。 根據以上分析可得知，因PbSe薄膜在可見光至近紅外光區具有吸收，且改質和燒結可以去除不導電的油酸官能基並增加薄膜結晶性，故PbSe/PCBM:P3HT元件的太陽光與紅外光光電轉換效率比PCBM:P3HT薄膜元件高。

In this research, we use solution phase method to fabricate PbSe that has different first absorption peak. The PbSe thin films are treated chemically in a solution of butylamine in acetonitrile to remove the surface oleate and the films are annealed in nitrogen. Subsequently, blend P3HT:PCBM composite (1: 0.8 wt %) dissolved in chlorobenzene was spin -casted at top of the PbSe thin film to fabricate solar cell device. In the experiment, we discover that change the solution of butylamine concentration, the immersion time and the annealing temperature and time, will affect the power conversion efficiency of solar cell. The thermal treatments of PbSe NC films were analysis by FTIR, TGA, and XRD; the result shows that oleate can be removed at certain annealing temperature, causing NCs growth and increasing the crystallinity. FTIR spectrum of modified PbSe thin films indicate that the amount of removal oleate increase with higher modified solution concentration and the longer soaking time. As shown by SEM image, the resulting modified films exist cracks. These cracks size become larger with increasing modified solution concentration, indicate that removed oleate attribute to decrease the distance of particles. Analysis by FTIR spectrum reveal an increasing amount of removal oleate at certain annealing temperature. The blend PCBM:P3HT solution was then spin-cast on top of the PbSe thin film. Subsequently, by Near IR-UV-Visible spectroscopy, we obtained a broaden absorption region from UV-Visible to Near IR of PCBM:P3HT spin-cast on top of the PbSe thin film. According to the analysis above, PbSe/PCBM:P3HT devices shows a better infrared power conversion efficiency and PCE than the devices without PbSe thin films.We attribute this enhancement to increased infrared power conversion efficiency and PCE as a result of the deposition of PbSe; the increasing absorption from UV-Visible to Near IR region and increasing crystallinity result from modification and annealing treatment of removal oleate.