Efficiency improvement of a nanostructured polymer solar cell employing atomic layer deposited Al2O3 as a passivation layer

• Hybrid solar cells based on silicon nanochannel and PEDOT:PSS have been demonstrated.
• ALD grown Al2O3 passivation (recombination barrier) layer was employed.
• The described device was fabricated by low-cost, solution based methods.
• The maximum PCE in excess of 9.5% has been achieved.

We report a hybrid heterojunction solar cell based on silicon nanochannel (SiNC) arrays and poly(3,4-ethylenedioxythiophane):poly-styrenesulfonate (PEDOT:PSS) with a power conversion efficiency (PCE) in excess of 9.50%. The described device is produced by spin coating the organic polymer PEDOT:PSS on SiNC arrays fabricated employing metal assisted electroless chemical etching methods. We utilized an ultrathin Atomic Layer Deposited (ALD) aluminum oxide (Al2O3) interface passivation layer between the SiNC arrays and PEDOT:PSS layer and its influence on the photovoltaic performance of the device is analyzed herein. An open circuit voltage (VOC) and a short circuit current density (JSC) as high as 565 mV and 28.4 mA/cm2, respectively, were achieved, which lead to a PCE of 9.52% for the optimized SiNC depth of 1.35 μm even without an antireflection coating and back surface field enhancement. The electrical performance of the described device is also analyzed in terms of the capacitance voltage (C–V) measurements collected at room temperature.

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