Organic donor, acceptor and buffer layers of small molecules prepared by OVPD technique for photovoltaics

摘要

Organic vapour-phase deposition (OVPD~®) is used for the growth of the organic solar cell component materials such as the donor copper phthalocyanine (CuPc), the acceptor fullerene C_(60), and electron-conducting buffer layers of bathocuproine (BCP) on Si < 1 0 0 > wafers and indium tin oxide (ITO) substrates on areas as large as 15 × 15 cm . By means of X-ray diffraction (XRD) analysis we show that under continuous operating conditions the source materials possess long-term stability. The CuPc, C_(60) and BCP thin film morphology and structure are characterised using scanning electron microscopy and XRD analysis. We demonstrate CuPc thin films with a highly folded surface morphology suitable for the preparation of solar cells with an interpenetrating donor-acceptor interface. The XRD diffraction patterns of the CuPc and C_(60) layers deposited under conditions appropriate for the preparation of organic solar cells show spectra typical for these materials. Mixed CuPc:C_(60) layers with controlled constituent ratios and layer thickness are deposited for the preparation of organic solar cells. First ITO/CuPc:C_(60)/Al organic photovoltaic devices are prepared with an efficiency of ~1% (conditions AM 1.5).