Lateral Fully Organic P–N Diodes Created in a Single Donor–Acceptor Copolymer

Abstract

P–N junctions exist in many solid‐state organic devices, such as light‐emitting diodes, solar cells, and thermoelectric devices. Creating P–N junctions by bulk chemical doping in a single organic material (like silicon doped by boron and phosphorus) may capitalize the vast scientific and technological groundwork established in the inorganic semiconducting field. However, high‐performance single‐organic‐material P–N junctions are seldom reported, because the diffusion of the dopant counterions often leads to transient rectification properties. Herein, a new type of lateral fully organic diodes created in single donor–acceptor (D–A) copolymer films with only one P‐type dopant is reported. The achieved lateral devices exhibit high current densities of ≈3.83 A cm−2 and a high rectification ratio of ≈2100, which are beyond the requirements for high‐frequency identification tags. The P‐ to N‐type polarity switching mechanism is proposed after spectroscopic and structural tests. Decent stability of the organic diode is obtained, which is due to the long channel length and low diffusion speed of the large size of dopants. This work opens the opportunities to create P–N junctions in ways of silicon‐based inorganic semiconductors and promises new opportunities for integrating organic materials for flexible and printable organic devices.

Revealing the Enhanced Thermoelectric Properties of Controllably Doped Donor‐Acceptor Copolymer: The Impact of Regioregularity

“…To further investigate the interaction between semiconduc tors and dopants, and based on the mechanism that has been reported, [2,[81][82][83] we speculate a plausible reaction mechanism for the FeCl positions that could interact with Fe 3+ . Due to the difficulty in locating these positions on the regiorandom PRF, we set X = F and Y = H as examples in Figure 1b and analogized the rest situations accordingly.…”

Molecular engineering accelerated polarity switching enabling high-performance n-type organic thermoelectrics

“…38 Nevertheless, a massive gap still exists in contrast to p-type OTEs, [39][40][41] especially the ineluctable n-doping procedure which largely restricts the development of desirable n-type organic semiconductors. [42][43][44][45] Actually, the polarity (or the sign of S) of the conducting polymers does not entirely depend on the classication of chemical doping (i.e., p-or n-doping), [46][47][48] since the dominating charge carriers that are associated with the conduction can be inuenced by numerous variables, including temperature, pressure, charge transfer models and doping levels. [49][50][51][52] For example, Shuai et al, demonstrated that the temperaturedependence of S exhibits diverse tendencies differentiated by one-or two-band charge transfer models, leading to the sign of S covering both positive and negative along with the varying temperature.…”

“…Consequently, a very high PF of 20.7 AE 0.7 mW m À1 K À2 was achieved by PIDT-HTBTDF with 0.3 M FeCl 3 , which represents the highest value of n-type OTEs by a simple pdoping technique. 47,48,52,54…”

Efficient and air-stable n-type doping in organic semiconductors

“…Besides, the excessive p-type doping could be applied in n-type OSC materials. 67,173–175 The strong oxidant, FeCl 3 was used to dope p-type semiconducting polymer PDPP-4T, and the Seebeck coefficients changed from positive (p-type) to negative (n-type) with increasing doping levels, which might be attributed to the switch of dominant charge carriers from the hole to electron, and transporting modes from hopping to band-like. The high n-type power factor of 9.2 μW m −1 K −2 achieved in this doped system would make this unique doping way very attractive in developing air-stable n-type doped OSCs.…”