Unveiling the Impact of Downscale Reactions on <scp>P3HT</scp> Synthesis: A Comprehensive Exploration of Properties and Photovoltaic Device Performance

ABSTRACT In photovoltaic polymer synthesis research, it is routine to adapt chemical reactions while respecting the stoichiometric proportions of the reagents. Generally, researchers reduce the amounts of chemical reagents to save materials or adjust the necessary quantity according to the need to avoid waste, as these materials undergo chemical changes and alterations in their properties over time, compromising the performance of their photovoltaic devices. P3HT is considered a reference in the field of solar cells. This study demonstrated that downscaling P3HT synthesis significantly influences the optoelectronic properties and photovoltaic device performance. To further investigate this effect, P3HT devices were fabricated on large‐area substrates with varying pixel sizes, allowing for a comprehensive assessment of the impact of laboratory‐scale synthesis reductions and their potential implications for market applications. The scale‐down synthesis with 50% of the reaction system decreases optoelectronic properties and the performance of a photovoltaic device. The standard synthesis performed in duplicate also demonstrated devices with efficiency similar to the scale‐down method. Synthesis using proportions close to 3.5 g of monomer resulted in better optoelectronic properties, molar mass, and devices with efficiencies of up to 3.04% ± 0.11% for a 0.16 cm 2 pixel and 2.23% ± 0.14% for a large area pixel of 1 cm 2 .