High-Performance Chlorophyll-b/Si Nanowire Heterostructure for Self-Biasing Bioinorganic Hybrid Photodetectors

As one kind of ecofriendly organic semiconductor materials, chlorophyll has attracted great attention with useful optical properties. Although pigments such as chlorophyll-a (Chl-a) are explored widely, chlorophyll-b (Chl-b) is rarely studied even though it possesses outstanding optical properties with impressive stability. Here, Chl-b is extracted from spinach leaves using a very simple and cost-effective method to study its potential use on Si nanowire (NW) heterostructures having volume concentration varying from 0 to 6%. In comparison to the control Si NW device, the Chl-b/SiNW heterostructure exhibits superior optoelectronic performances including high on/off ratio (∼103), good external quantum efficiency (∼208%), high responsivity (∼0.73 A/W), improved detectivity (∼2.2 × 1012 Jones), and relatively faster response time (<1 s) under 435 nm illumination. In addition, it offers quite promising values of the abovementioned figure of merits of a photodetector over the wide spectral range from 350–1100 nm. This low-cost and high-sensitivity Chl-b/SiNW heterostructure device thus opens up challenging research possibilities for green energy conversion and biophotonic applications on Si-compatible complementary metal–oxide–semiconductor platforms.