Ubiquitous carrier harvesting in organic solar cells with embedded indium–tin-oxide nano-electrodes

• Ubiquitous carrier harvesting characteristics of embedded indium–tin-oxide nano-electrodes is demonstrated for organic solar cells.
• Compared to planar electrode reference, the internal quantum efficiency in new device exhibits broadband enhancements with excellent angular response, indicating that charge collection is insensitive to the distribution of carrier generation.
• This attribute is very desirable to organic thin film devices operated under diffused ambient light and with flexible substrates.

Bulk heterojunction in organic solar cells allows adequate interfaces for the dissociation of photo-generated excitons. However, the intermixed donor- and acceptor-like materials do not guarantee successful carrier transport and collections. In this work, we demonstrate ubiquitous carrier harvesting characteristics by using embedded indium–tin-oxide nano-electrodes (NEs) with a conformal electro-polymerized coating of a hole conducting layer. Compared to its planar electrode counterpart, this device exhibits internal quantum efficiency insensitive to the distribution of carrier generation, as determined by angle-resolved absorption spectroscopy and photocurrent characteristics. The ubiquitous carrier harvesting characteristics offer a viable solution to organic thin-film devices fabricated on flexible substrates or operated under diffused ambient light.

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