Princeton University

School of Engineering & Applied Science

Creating Highly Efficient Carrier Injection or Collection Contacts via Soft-contact Lamination of p-doped Interlayers

An Dai
J401 Engineering Quadrangle
Monday, October 19, 2015 - 1:00pm

Contacts are of great importance for the design and development of efficient and long-lived electronic devices. Low resistance contacts on inorganic semiconductors have traditionally been achieved by heavy doping of the semiconductor interface. This technique has been successfully applied also to organic molecular semiconductors, in which dopants can be precisely positioned via controlled vacuum co-deposition. However, precise interface confinement of dopants in a solution-processed film, deposited by spin-coating or printing, is not possible. We present here a versatile approach, which consists in physically transferring onto the active layer of the device via soft-contact lamination an ultra-thin film of doped polymer. This film, separately spin-coated from a solution containing a controlled amount of soluble dopant, creates a high-conductivity layer with controllable work function, that is also electronically and chemically compatible with the organic active layer. This approach affords unprecedented flexibility in the positioning of doped regions in organic devices. An application to organic solar cells is demonstrated, with good efficiency. Stability studies of such devices also shows promising results.