Systematic modification of the indium tin oxide work function via side-chain modulation of an amino-acid functionalization layer

Enhancement of electronic effects at a biomolecule-inorganic interface by multivalent interactions

The binding of peptides and proteins through multiple weak interactions is ubiquitous in nature. Biopanning has been used to "hijack" this multivalent binding for the functionalization of surfaces. For practical applications it is important to understand how multivalency influences the binding interactions and the resulting behaviour of the surface. Considering the importance of optimization of the electronic properties of surfaces in diverse electronic and optoelectronic applications, we study here the relation between the multivalency effect and the resulting modulation of the surface work function. We use 12-mer peptides, which were found to strongly bind to oxide surfaces, to functionalize indium tin oxide (ITO) surfaces. We show that the affinity of the peptides for the ITO surface, and concurrently the effect on the ITO work function, are linearly affected by the number of basic residues in the sequence. The multivalent binding interactions lead to a peptide crowding effect, and a stronger modulation of the work function for adodecapeptide than for a single basic amino acid functionalization. The bioderived molecular platform presented herein can pave the way to a novel approach to improve the performance of optoelectronic devices in an eco-friendly manner.

Inverted Si:PbS Colloidal Quantum Dot Heterojunction-Based Infrared Photodetector

Silicon and PbS colloidal quantum dot heterojunction photodetectors combine the advantages of the Si device and PbS CQDs, presenting a promising strategy for infrared light detecting. However, the construction of a high-quality CQDs:Si heterojunction remains a challenge. In this work, we introduce an inverted structure photodetector based on n-type Si and p-type PbS CQDs. Compared with the existing normal structure photodetector with p-type Si and n-type PbS CQDs, it has a lower energy band offset that provides more efficient charge extraction for the device. With the help of Si wafer surface passivation and the Si doping density optimization, the device delivers a high detectivity of 1.47 × 10¹¹ Jones at 1540 nm without working bias, achieving the best performance in Si/PbS photodetectors in this region now. This work provides a new strategy to fabricate low-cost high-performance PbS CQDs photodetectors compatible with silicon arrays.