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

Abstract

In this review, the key factors that determined air stability and doping efficiency of n-type doped organic semiconductors were summarized, together with the discussion of their applications in organic electronics.

Electron-Transporting Properties and Ultrasmall Band Gap of BODIPY-Based Conjugated Polymers: Teach an Old Dog New Tricks

“…Organic thermoelectrics are promising for flexible and wearable energy-supplying devices. , The development of n-type organic thermoelectric materials lags far behind that of the p-type counterpart in view of material diversity and thermoelectric performance. − P-α-V possesses a low-lying LUMO energy level, a well-delocalized negative charge distribution, and high electron mobility. This motivated us to explore the n-type thermoelectric performance of P-α-V .…”

The Quest for Air Stability in Organic Semiconductors

“…The remarkable improvement was attributed to not only thermodynamic considerations but also largely the formation of thicker films with a self-encapsulation effect. The discrepancy between the LUMO level requirement for air-stable OFETs compared to a stand-alone n-doped films can also be attributed to this effect as illustrated in Figure a. , In devices like OFETs, charge accumulation occurs within several monolayers (≈1–5 nm) , buried at the interface of the OSC/dielectric layer. In a bottom-gate OFET configuration, the thickness of the neutral OSC layer is approximately 10–100 times larger than the thickness of the conductive channel, thereby forming a self-encapsulation to shield this doped region.…”

Hyperbranched Perylene Diimide Polymers as Electron Transport Layers for Efficient Organic Solar Cells

“…To date, several hyperbranched polymers have been applied in OSCs as interlayers, such as poly­(ethyleneimine) (PEI) and its derivatives, which are nonconjugated insulating polymers. , Although they have good alcohol solubility and solution processability, their mobility and conductivity are low, often resulting in limited device performance as ETL. − Therefore, it is necessary to design new efficient hyperbranched polymer ETLs for OSCs to improve their performance and stability. Perylene diimide (PDI), with a very planar structure, high electron affinity, and high photochemical stability, has been suggested as a high-mobility charge transport material for organic optoelectronic devices. − Moreover, the conductivity of PDI derivatives can be enhanced by doping with different anions via charge transfer processes. , However, hyperbranched polymer ETLs based on PDI have been rarely reported since most PDI-based ETL materials are small molecules, such as PDIN, PDINO, and PDINN. , …”

“…33−35 Moreover, the conductiv- ity of PDI derivatives can be enhanced by doping with different anions via charge transfer processes. 36,37 However, hyperbranched polymer ETLs based on PDI have been rarely reported since most PDI-based ETL materials are small molecules, such as PDIN, PDINO, and PDINN. 38,39 Herein, we synthesized two novel alcohol-soluble hyperbranched polymers, HPDIN-B01 and HPDIN-B02, by integrating PDI units with the "A2" + "B3" methodology, 24 which is commonly used for preparing hyperbranched polymers (Figure 1a).…”