and are believed to be key to sustainably overcoming the terawatt energy challenge the world currently faces. [1][2][3] The field of solar energy harvesting, previously dominated by inorganic materials, has in recent times witnessed the rapid ascent of organic materials in device designs. [4] In particular, much of the progress in this field has been driven by bioinspiration with nature's photosynthetic (PS) apparatus as a model material. [5][6][7] The aim of exploiting nature's designs for the harnessing of solar energy has attracted considerable efforts in the areas of artificial photosynthesis, [8,9] bio-photovoltaics and bio-electrochemical cells. [10][11][12][13][14] The "biomimetic solar cell," an application long sought after, aims to mimic the architecture of nature's reaction center (RC) and light-harvesting (LH) complexes in a fully artificial photosynthetic device for direct "solar electricity" generation. [15] Although the basic design principle of a dye-sensitized solar cell comes closer to this idea, [16] it is undeniably far from having any structural similarity with photosynthetic proteins, and developing supramolecular solar cells with artificial RCs [17] or other protein mimics has been extremely challenging. [18] Alongside the development of artificial photosynthetic systems, there have also been attempts to directly employ natural photosynthetic materials such as bacterial cells, [19][20][21] pigment proteins, [22][23][24][25][26][27][28][29] and membranes [30,31] as photoactive components for both direct electricity generation and fuel molecule synthesis.While, on the one hand, fully artificial photosynthetic systems lack the nanoscale architectural sophistication found in natural photosystems, on the other hand, natural photosystems are not always sufficiently robust or efficient outside their native environments. These and other factors limit the performance of a device employing solely natural or artificial materials as the photoactive component. [32] Bridging the two approaches, the idea of semiartificial photosynthetic systems is now gaining attention as it offers advantages over purely artificial or biological systems. [32,33] The concept has already shown signs of success in fuel generation by photo-electrochemical water splitting. [34,35] Direct electric current generation has also been studied in a wide variety of biohybrid devices, combining different photosynthetic microorganisms [19,20,36] and Semiartificial photosynthetic systems have opened up new avenues for harvesting solar energy using natural photosynthetic materials in combination with synthetic components. This work reports a new, semiartificial system for solar energy conversion that synergistically combines photoreactions in a purple bacterial photosynthetic membrane with those in three types of transition metal-semiconductor Schottky junctions. A transparent film of a common transition metal interfaced with an n-doped silicon semiconductor exhibits an in-plane potential gradient when a light-penetration variance is esta...
