Near-infrared sensitive small molecule organic photovoltaic cells based on chloroaluminum phthalocyanine

The use of chloroaluminum phthalocyanine (ClAlPc) as a donor and ${\mathrm{C}}_{60}$ as an acceptor in planar double heterojunction organic photovoltaic cells with response extending into the near infrared is demonstrated. X-ray diffraction indicates that under the conditions used in this study ClAlPc grows as an amorphous film. Although the absorption and film morphology show no dependence on growth rate, device performance is optimized at a growth rate of $0.5\mathrm{\AA }∕\mathrm{s}$ , producing cells whose best performance gives an open circuit voltage of $0.68\pm 0.01\mathrm{V}$ , a responsivity of $0.062\pm 0.007\mathrm{A}∕\mathrm{W}$ , a fill factor of $0.50\pm 0.04$ , and a power conversion efficiency of $2.1\pm 0.1\%$ under simulated AM1.5G, 1 sun intensity illumination. This cell also displays low dark current under reverse bias, $2.4\times {10}^{-8}\mathrm{A}∕{\mathrm{cm}}^2$ at $-1\mathrm{V}$ .