# Tuning Optical Absorption and Device Performance in P3HT:PCBM Organic Solar Cells Using Annealed Silver Thin Films

## TL;DR

This paper shows how annealed silver films can improve the efficiency of organic solar cells by boosting light absorption and charge transport.

## Contribution

The novel use of ultrathin, annealed Ag/AgO interfacial layers to enhance both optical absorption and device performance in organic solar cells.

## Key findings

- A 1 nm AgO layer annealed for 2 h increased power conversion efficiency by 6%.
- Annealed Ag films improved light absorption by 25% due to localized surface plasmon resonance.
- Series resistance was reduced by 11%, aiding efficient hole extraction.

## Abstract

In this study, we investigated the effect of annealing ultrathin silver (Ag) films of varying thicknesses (1–6 nm) on both their optical absorption and the performance of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) organic solar cells (OSCs). The Ag films were deposited on indium tin oxide (ITO) anodes and annealed at 300 °C for 1–2 h to modify the anodic interface. The optical and electrical properties of the resulting devices were systematically characterized and optimized. The results revealed that a 1 nm AgO layer annealed for 2 h significantly enhanced the device performance, yielding a 6% increase in power conversion efficiency compared to the standard configuration. This improvement is attributed to two main factors: (i) a 25% increase in light absorption of the AgO/P3HT:PCBM film due to localized surface plasmon resonance of Ag nanoparticles and (ii) an 11% reduction in series resistance resulting from the favorable alignment of the Ag work function with the ITO anode and the polymer HOMO, which facilitates efficient hole extraction. These findings highlight the potential of ultrathin, annealed Ag/AgO interfacial layers as an effective strategy to enhance light absorption and charge transport in OSCs.