# Graphene Oxide–Enamino-Xanthene Charge-Transfer Hybrids as High-Performance Sensitizing Interfaces for TiO2 Photoanodes

## TL;DR

This paper introduces a new hybrid material combining graphene oxide and a dye to improve the performance of solar energy conversion systems.

## Contribution

The novel contribution is the synthesis of a graphene oxide–enamino-xanthene hybrid that enhances TiO2 photoanode performance.

## Key findings

- The hybrid material shows suppressed fluorescence and altered electronic transitions due to strong interface interactions.
- Photoanodes with the hybrid layer exhibit a 3.5-fold increase in photocurrent and faster saturation kinetics under visible light.
- Electrochemical analysis confirms reduced interface resistance and improved charge carrier mobility.

## Abstract

Hybrid materials
that combine visible-light absorption with efficient
charge separation across interfaces are essential for advancing photoelectrochemical
(PEC) energy conversion technologies. In this study, we report the
synthesis of charge-transfer hybrids composed of graphene oxide (GO)
and enamino-xanthene (NH2-X) dyes, prepared via a simple
and sustainable liquid-phase mixing approach. Spectroscopic analyses
reveal strong interface interactions between GO and NH2-X, leading to suppressed fluorescence and altered electronic transitions,
consistent with ground-state charge-transfer processes. When interfaced
with TiO2 as a sensitizing layer, the resulting photoanodes
deliver a 3.5-fold enhancement in photocurrent, faster saturation
kinetics, and improved photopotential generation under visible-light
illumination. Electrochemical impedance spectroscopy confirms reduced
interface resistance and enhanced charge carrier mobility at both
solid–solid and solid–liquid interfaces. The synergistic
integration of GO and NH2-X establishes a high-performance
sensitizing interface for TiO2 photoanodes, offering a
scalable and environmentally benign route toward advanced PEC applications.