Comparative study of industry-compatible indium-oxide-based sputtered transparent electrodes for transparent perovskite solar cells

Abstract The growing demand for thin-film optoelectronic and energy-harvesting devices based on sensitive photonic materials, such as organic semiconductors, perovskite, and emerging bioelectronics, has underscored the critical need for low to room temperature (RT) deposition of transparent electrodes (TEs). This study has focused on establishing a deposition mechanism to obtain highly conductive and transparent indium zinc oxide (IZO) and indium tin oxide (ITO) TEs at RT. We have conducted a comparative study between amorphous IZO (a-IZO) and polycrystalline ITO (c-ITO) for applications in transparent perovskite solar cells (T-PSCs). The superstrate-architecture of T-PSCs exhibit better performance with a-IZO as a rear electrode than with c-ITO. The primary reasons behind the improvement in a-IZO-based devices is the low sheet resistance ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>22.41</mml:mn> </mml:mrow> </mml:math> Ω sq −1 ), high carrier mobility <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mo>(</mml:mo> <mml:mrow> <mml:mi>μ</mml:mi> <mml:mo>=</mml:mo> <mml:mn>32.12</mml:mn> <mml:mtext> </mml:mtext> <mml:msup> <mml:mrow> <mml:mtext>cm</mml:mtext> </mml:mrow> <mml:mn>2</mml:mn> </mml:msup> <mml:msup> <mml:mtext>V</mml:mtext> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:msup> <mml:mtext>s</mml:mtext> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> <mml:mo>)</mml:mo> </mml:mrow> <mml:mo>,</mml:mo> </mml:mrow> </mml:math> low roughness ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mtext>RMS</mml:mtext> <mml:mo>∼</mml:mo> <mml:mn>1.05</mml:mn> <mml:mtext> </mml:mtext> <mml:mtext>nm</mml:mtext> </mml:mrow> </mml:math> ), and high transmittance in the infrared range ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>T</mml:mi> <mml:mi>a</mml:mi> <mml:mi>v</mml:mi> <mml:mo>∼</mml:mo> <mml:mn>83.5</mml:mn> <mml:mi mathvariant="normal">%</mml:mi> </mml:mrow> </mml:math> ) compared to c-ITO. This study also presents the first comprehensive understanding of the presence of substantial interface defects which limit the wider adaptation of traditionally used c-ITO in T-PSCs, addressing a significant gap in the literature. Moreover, those interfacial defects have been the primary factor contributing to its lower power conversion efficiency (PCE) of 15.84%, compared to the 18.22% achieved by a-IZO-based devices. Thus, this study elucidates the underlying mechanisms that account for the widespread adoption of a-IZO in the development of T-PSCs.