This study investigates the transparent conductive oxides (TCOs) as front contact for thin-film solar cell applications by developing a bilayer design that decouples the optical and electrical functionalities. The bilayer front contact structure combines hydrogenated indium oxide (IOH) and non-intentionally doped zinc oxide (ZnO) materials. This design achieves enhanced optoelectrical properties with a mobility of 120 cm²/Vs and a carrier density of 1.97·10¹⁹ cm^-3. Notably, the bilayer outperforms the expected average of its constituent layers in both transparency and conductivity, reflecting the benefits of optimized layer architecture. When integrated as the front electrode in a hydrogenated nanocrystalline silicon (nc-Si:H) solar cell, the IOH/ZnO bilayer yields a fill factor of 64.56 % and a power conversion efficiency of 7.85 %. When using an ITO front contact, the nc-Si:H solar cell reveals a fill factor of 56.27 % and an efficiency of 6.80 %. By successfully decoupling optical and electrical properties, the optimized IOH/ZnO bilayer offers a significant advancement over single-layer TCO configurations, presenting an innovative pathway for enhanced performance in thin-film solar cell technology.

Our study focuses on the optimization of front contact design by exploring a novel bilayer configuration that employs transparent conductive oxides (TCOs) to enhance the efficiency of thin-film silicon solar cells. The TCOs investigated include sputtered hydrogenated indium oxide (IOH), cerium-doped indium oxide (ICO), cerium and hydrogen co-doped indium oxide (ICOH), and intrinsic zinc oxide (i-ZnO). We highlight the suitability of these TCOs in a bilayer design, first analyzing their opto-electrical properties as monolayers and subsequently in bilayer configurations. The IOH/i-ZnO bilayer architecture, in particular, demonstrates promising opto-electrical properties on both flat glass and micro-textured glass substrates. IOH/i-ZnO on flat glass substrate demonstrates remarkable mobility (143.44 cm²/Vs) and a carrier concentration in the order of 10¹⁹cm^-3. The mean of reflectance (R) trends consistently exceeds 80%, while the mean of transmittance (T) trends falls below 20% beyond 500 nm. The interference effects within the bilayers are minimized for designs on micro-textured glass, preserving values within a desirable range. These findings represent an innovative approach to front contact design for thin-film silicon solar cells, emphasizing the potential of bilayer configurations to advance solar cell technology.