Single Component Organic Solar Cells Based on Oligothiophene‐Fullerene Conjugate

Abstract

A new donor (D)-acceptor (A) conjugate, benzodithiophene-rhodanine-[6,6]-phenyl-C 61 butyric acid methyl ester (BDTRh-PCBM) comprising three covalently linked blocks, one of p-type oligothiophene containing BDTRh moieties and two of n-type PCBM, is designed and synthesized. A single component organic solar cell (SCOSC) fabricated from BDTRh-PCBM exhibits the power conversion efficiency (PCE) of 2.44% and maximum external quantum efficiency of 46%, which are the highest among the reported efficiencies so far. The SCOSC device shows efficient charge transfer (CT, ≈300 fs) and smaller CT energy loss, resulting in the higher open-circuit voltage of 0.97 V, compared to the binary blend (BDTRh:PCBM). Because of the integration of the donor and acceptor in a single molecule, BDTRh-PCBM has a specific D-A arrangement with less energetic disorder and reorganization energy than blend systems. In addition, the SCOSC device shows excellent device and morphological stabilities, showing no degradation of PCE at 80 °C for 100 h. The SCOSC approach may suggest a great way to suppress the large phase segregation of donor and acceptor domains with better morphological stability compared to the blend device.

Mesogenic complementary absorbing dyads based on porphyrin and perylene units

“…Moreover, several major advantages, such as a considerable simplification of device fabrication, stabilization of the morphology of the active material, and efficient (or fast) charge separation can be expected in the single-component OSCs [11]. At present, the PCE for single-component OSCs has surpassed 2% [12,15,17], which is lower than that of BHJ solar cells. This is because the design of electron donor-acceptor molecules for efficient single-component OSCs is in fact difficult.…”

“…In spite of these remarkable performances, the realization of solution-processed BHJ solar cells still poses a number of problems related to both the nature of the active materials and the fabrication process [11]. For example, the finecontrol of phase separation and achieving high chargecarrier mobility in active layers are still very difficult with BHJ solar cells [ As another interesting strategy, electron donoracceptor dyad, triad, multiad and block copolymer molecules or all-in-one molecules where the electron donor (D) and acceptor (A) units are covalently linked in a single molecule have been reported for their potential as photovoltaic materials [12,[14][15][16][17][18][19]. These single-component photovoltaic materials possess multifunctions such as light harvesting, exciton dissociation and electron and hole transport.…”

The Dawn of Single Material Organic Solar Cells

“…[106] The electron mobility of the three compounds determined in OFETs gave much higher value (1.5 × 10 −3 cm 2 V −1 s −1 ) for 29a with the shortest linker than for 29b and 29c (6.1 × 10 −4 and 4.5 × 10 −4 cm 2 V −1 s −1 ), respectively. [111] This type of hybrid oligomeric conjugated structure had been previously used as molecular donor in highly efficient bicomponent BHJs. On the other hand, it was reported that hole mobilities were too low to be detected in OFET devices.…”

“…[111] Stability tests performed at 80 °C under inert atmosphere showed that a reference cell based on a blend of PC 61 BM with a donor analog to 32 but devoid of fullerene (32b) shows a decay of PCE to 80% of the initial value after 10 min, associated with large phase segregation, suggesting poor morphological stability. [111] Stability tests performed at 80 °C under inert atmosphere showed that a reference cell based on a blend of PC 61 BM with a donor analog to 32 but devoid of fullerene (32b) shows a decay of PCE to 80% of the initial value after 10 min, associated with large phase segregation, suggesting poor morphological stability.…”

“…In this regard, some recent works indicate that within certain conditions, dyads with a direct fixation of a linearly conjugated chain on C 60 can lead to materials with interesting photovoltaic properties. [111] Copyright 2018, American Chemical Society. Thus, a SMOSC based on 33 presents an EQE of 0.10 at 700 nm.…”