Deep HOMO Level Research Articles

Understanding the Impact of SAM Fermi Levels on High Efficiency p-i-n Perovskite Solar Cells.

Completing the picture of the underlying physics of perovskite solar cell interfaces that incorporate self-assembled molecular layers (SAMs) will accelerate further progress in p-i-n devices. In this work, we modified the Fermi level of a nickel oxide-perovskite interface by utilizing SAM layers with a range of dipole strengths to establish the link between the resulting shift of the built-in potential of the solar cell and the device parameters. To achieve this, we fabricated a series of high-efficiency perovskite solar cells with no hysteresis and characterized them through stabilize and pulse (SaP), JV curve, and time-resolved photoluminescence (TRPL) measurements. Our results unambiguously show that the potential drop across the perovskite layer (in the range of 0.6-1 V) exceeds the work function difference at the device's electrodes. These extracted potential drop values directly correlate to work function differences in the adjacent transport layers, thus demonstrating that their Fermi level difference entirely drives the built-in potential in this device configuration. Additionally, we find that selecting a SAM with a deep HOMO level can result in charge accumulation at the interface, leading to reduced current flow. Our findings provide insights into the device physics of p-i-n perovskite solar cells, highlighting the importance of interfacial energetics on device performance.

A Fluorinated Imide-Functionalized Arene Enabling a Wide Bandgap Polymer Donor for Record-Efficiency All-Polymer Solar Cells.

All-polymer solar cells (all-PSCs) present compelling advantages for commercial applications, including mechanical durability and optical and thermal stability. However, progress in developing high-performance polymer donors has trailed behind the emergence of excellent polymer acceptors. In this study, we report a new electron-deficient arene, fluorinated bithiophene imide (F-BTI) and its polymer donor SA1, in which two fluorine atoms are introduced at the outer β-positions in the thiophene rings of BTI to fine-tune the energy levels and aggregation of the resulting polymers. SA1 exhibits a deep HOMO level of -5.51 eV, a wide bandgap of 1.81 eV and suitable miscibility with the polymer acceptor. Polymer chains incorporating F-BTI result in a highly ordered π-π stacking and favorable phase-separated morphology within the all-polymer active layer. Thus, SA1 : PY-IT-based all-PSCs exhibit an efficiency of 16.31 % with excellent stability, which is further enhanced to a record value of 19.33 % (certified: 19.17 %) by constructing ternary device. This work demonstrates that F-BTI offers an effective route for developing new polymer materials with improved optoelectronic properties, and the emergence of F-BTI will change the scenario in terms of developing polymer donor for high-performance and stable all-PSCs.

A Fluorinated Imide‐Functionalized Arene Enabling a Wide Bandgap Polymer Donor for Record‐Efficiency All‐Polymer Solar Cells

AbstractAll‐polymer solar cells (all‐PSCs) present compelling advantages for commercial applications, including mechanical durability and optical and thermal stability. However, progress in developing high‐performance polymer donors has trailed behind the emergence of excellent polymer acceptors. In this study, we report a new electron‐deficient arene, fluorinated bithiophene imide (F‐BTI) and its polymer donor SA1, in which two fluorine atoms are introduced at the outer β‐positions in the thiophene rings of BTI to fine‐tune the energy levels and aggregation of the resulting polymers. SA1 exhibits a deep HOMO level of −5.51 eV, a wide bandgap of 1.81 eV and suitable miscibility with the polymer acceptor. Polymer chains incorporating F‐BTI result in a highly ordered π–π stacking and favorable phase‐separated morphology within the all‐polymer active layer. Thus, SA1 : PY‐IT‐based all‐PSCs exhibit an efficiency of 16.31 % with excellent stability, which is further enhanced to a record value of 19.33 % (certified: 19.17 %) by constructing ternary device. This work demonstrates that F‐BTI offers an effective route for developing new polymer materials with improved optoelectronic properties, and the emergence of F‐BTI will change the scenario in terms of developing polymer donor for high‐performance and stable all‐PSCs.

Development of Two Novel Dibenzosilole-Based Conjugated Polymers with Thieno[3,4-c]pyrrole-4,6-dione for Use in Polymer Solar Cells

The donor-acceptor (D-A) strategy has proven to be one of the most effective methods for tuning the band gaps, absorption characteristics, and optoelectronic properties in conjugated polymers. Two novel D-A conjugated polymers, PDBSTPD-1T and PDBSTPD-2T, were synthesized using dibenzosilole (DBS) and thieno[3,4-c]pyrrole-4,6-dione (TPD) as the building blocks. These polymers were linked through either a single thiophene or two thiophene rings as π-bridges and were copolymerized using a Suzuki coupling reaction. The effect of the incorporation of the different π-bridges on the electrical/optical properties of the prepared copolymers was also investigated. The synthesized polymers, PDBSTPD-1T and PDBSTPD-2T, were soluble in organic solvents and demonstrated high molar mass along with excellent thermal stability. The conjugation of the electron-accepting TPD unit with the electron-donating DBS unit produced relatively deep HOMO levels, which were fine-tuned to be −5.44 and −5.36 eV via the addition of the different π-bridges. PDBSTPD-1T and PDBSTPD-2T displayed absorption wavelengths between 350 and 650 nm with high Eg opt of 2.01 and 1.97 eV, respectively. X-ray diffraction analysis presented several diffraction peaks, and the π-π stacking distances of PDBSTPD-1T and PDBSTPD-2T were 3.45 and 3.65°A, respectively.

Evaluating Fluorinated-Aniline Units with Functionalized Spiro[Fluorene-9,9'-Xanthene] as Hole-Transporting Materials in Perovskite Solar Cells and Light-Emitting Diodes.

In the field of perovskite optoelectronics, developing hole-transporting materials (HTMs) on the spiro[fluorene-9,9'-xanthene] (SFX) platform is one of the current research focuses. The SFX inherits the merits of spirobifluorene in terms of the configuration and property, but it is more easily derivatized and regulated by virtue of its binary structure. In this work, we design and synthesize four isomeric SFX-based HTMs, namely m-SFX-mF, p-SFX-mF, m-SFX-oF, and p-SFX-oF, through varying the positions of fluorination on the peripheral aniline units and their substitutions on the SFX core, and the optoelectronic performance of the resulting HTMs is evaluated in both perovskite solar cells (PSCs) and light-emitting diodes (PeLEDs) by the vacuum thermal evaporating hole-transporting layers (HTLs). The HTM p-SFX-oF exhibits an improved power conversion efficiency of 15.21% in an inverted PSC using CH3NH3PbI3 as an absorber, benefiting from the deep HOMO level and good HTL/perovskite interface contact. Meanwhile, the HTM m-SFX-mF provides a maximum external quantum efficiency of 3.15% in CsPb(Br/Cl)3-based PeLEDs, which is attributed to its perched HOMO level and shrunken band-gap for facilitating charge carrier injection and then exciton combination. Through elucidating the synergistic position effect of fluorination on aniline units and their substitutions on the SFX core, this work lays the foundation for developing low-cost and efficient HTMs in the future.

‘Exploration of photovoltaic behavior of bithiophene-functionalized dispiro-oxepine based hole-transporting materials for efficient perovskite solar cells’

Perovskite solar cells (PSCs) have received great attention from researchers due to their superior photovoltaic properties, high efficiency, and low cost. In this study, bithiophene dispiro-oxepine based five hole-transporting materials (DDOF1, DDOF2, DDOF3, DDOF4, and DDOF5) are designed by the substitution of end-capped acceptors via thiophene-based bridge to enhance the photovoltaic properties of PSCs. The results showed that designed HTMs have deeper HOMO levels (−4.88 eV to −5.04 eV), high solubility, and compatible stability with lower energy gaps (2.04 eV to 2.59 eV) than the reference (EHOMO = −4.55 eV, Eg = −3.49 eV) and Spiro-OMeTAD (EHOMO = −4.47 eV, Eg = −3.86 eV), which improved hole extraction and the open-circuit voltage in the PSCs. Moreover, the binding energy (0.41 eV to 0.46 eV) and TDM analysis indicated that DDOF1-DDOF5 HTMs have high charge mobility compared to the reference molecule DDOF (0.61 eV). The DDOF1-DDOF5 HTMs indicated anticipated higher power conversion efficiency and open-circuit voltage than the reference molecule. Overall, our findings proved that designed molecules are efficient HTMs for the manufacture of high-efficiency PSCs in the solar industry.

Hole injection control of electron blocking layer for broad recombination zone and low-efficiency roll-off in phosphorescent organic light emitting device

Organic Light-Emitting Diodes (OLEDs) require several organic layers, including carrier injection layers, charge transport layers, and light-emitting layers (EML). Recently, many panel companies have been using layers with a dual function of charge transport and blocking to simplify the layer structure. At the same time, efficient charge injection into the EML is required to improve the device characteristics. In particular, the hole injection properties are important in devices using phosphorescent emitters because it is a major factor in forming the broad recombination zone. This study reports the factors influencing the device performances using three OLEDs with different electron-blocking layers (EBL). By adjusting the EBL’s energy levels, it is possible to form a broad recombination zone and reduce hole accumulation and polaron-induced stress at the interface. In addition, the wide dispersion of exciton formation reduces the overcrowding of exciton which induces exciton quenching and relieves an efficiency roll-off at high luminance. Consequently, the external quantum efficiency of N-([1,1'-biphenyl]-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-11,11-dimethyl-11H-benzo[b]fluoren-3-amine with a relatively deep HOMO level is increased by more than 2% with a relaxed roll-off of 7% at 3000 cd/m2 and a device lifetime is increased fivefold compared to those of N-([1,1′-biphenyl]-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-11,11-dimethyl-11H-benzo[b]fluoren-2-amine with a relatively shallow HOMO level.

P‐161: Late‐News Poster: Non‐Toxic PEIE dual Interfacial layers for efficiency improvement in Quantum dot light‐emitting diodes

Quantum Dot Light‐Emitting Diode (QD‐LED) has the disadvantage of charge imbalance due to the deep HOMO level of QD itself and layer mixing due to the solution process despite its enormous advantage of high color purity and large display manufacturing. PEIE, introduced to prevent this, uses harmful 2‐ME solvents, and was evaluated to replace them with IPA, a harmless solvent. As a result, IPA secured more than twice the EQE to resolve the charge imbalance compared to 2‐ME, and equivalent EQE to protect EML. Finally, we verify that 2‐ME could be smoothly replaced with IPA.

Influence of end-capped engineering on 3-dimenional star-shaped triphenylamine-based donor materials for efficient organic solar cells

Star-shaped- triphenylamine-based (TPA) hole transporting materials (HTMs) are considered an up-and-coming candidate for developing efficient organic solar cells (OSCs). Therefore, we have designed partially oxygen bridged eight new novels (STRO1 – STRO8) and three-armed star-shaped HTMs with TPA core for the future development of efficient OSCs devices. Their photovoltaic, optical, and charge transport (CT) characteristics were studied and compared with the reference molecule (R). These designed materials have been characterized theoretically using various density functional theory (DFT) and time-dependent (TD-DFT) calculations. These planar configurated star-shaped molecules exhibited a red-shifted absorption, deeper HOMO levels, and improved extinction coefficients, enabling them to offer good phase separation morphology during blend formation. Furthermore, the distribution behavior of frontier molecular orbitals (FMOs), optical properties, open-circuit voltages, the density of states (DOS), transition density matrix (TDM), and reorganization energies of holes and electrons of the designed star-shaped molecules have been investigated. Besides, the complex study of STRO/PC61BM revealed the charge shifting process at the donor–acceptor interface. Therefore, our projected approach is a prerequisite in designing small molecule (SM)-based desirable photovoltaic materials for efficient OSCs, and light-emitting diodes (LEDs), and afterwards, these materials are suggested to the experimentalist for synthesis and to fabricate efficient photovoltaic devices.

Rational design of the S,N‐heteroacene‐based nonfullerene by introducing the fluorine atom for efficient high‐performance organic solar cells

AbstractFluorination has been established as an effective structural modification strategy to influence properties and has attracted attention in organic solar cells. Here, we design and synthesize three fused‐ring electron acceptors based on ladder‐type pentacyclic heteroacenes as the electron‐rich unit and 1,1‐dicyanomethylene‐3‐indanones with 0–2 fluorine substituents as the electron‐deficient units. Among these three molecules, two fluorine substituents nonfullerene acceptor, DTP‐2F exhibit strong absorption with high extinction coefficients and deep HOMO and LUMO level as compared with DTP‐0F and DTP‐1F. Device studies show that fluorinated nonfullerene acceptors (NFAs) lead to reduced VOC but increased JSC and FF, and therefore, the ultimate influence to efficiency depends on the compensation of VOC loss and gains of JSC and FF. Furthermore, fluorination affect to film morphology and miscibility between donor and acceptor. The fluorination of NFAs is one of the best design method of the donor and acceptor materials for efficient high‐performance organic solar cell.

Chlorinated phthalimide polymer donor as ultra-wide bandgap and deep HOMO guest for achieving highly efficient polymer solar cells

Quaternary approach has been receiving more and more attention due to its effectiveness in improving solar cell performance, while synthesis/selection of the fourth component is yet a key issue. Herein, we report a chlorinated phthalimide based donor polymer (namely PhI-Cl) having an ultra-wide bandgap (2.10 eV) and a deep HOMO (−5.58 eV) level. Addition of PhI-Cl as the third component of PM6:Y6 and the fourth of PM6:Y6:PC71BM increases both hole and electron mobilities and gives rise to more balanced charge carriers mobilities. Both the short-circuit current-density and fill-factor are increased and open-circuit voltage is well maintained, delivering 17.0% and 18.1% efficiencies, respectively. These results demonstrate that chlorination on the side thiophene of phthalimide-based donor polymer is a way to make deep HOMO and ultra-wide bandgap donor polymer guest used for highly efficient ternary and quaternary strategies.

Synthesis and characterization of polythiophene containing side chain electron acceptor for OPV

The two new semiconducting polymers, poly((sexithiophene-5,5'''''-diyl)bis(tridecan-1-one))(PSTTO) and poly((sexithiophene-5,5'''''-diyl)bis(tridecan-1-one)bithiophene) (PSTTOBT), are synthesized and characterized. PSTTO and PSTTOBT have backbone donor and side chain acceptor structure. Compare to poly(3-hexylthiophene), both polymers had deep HOMO levels of 5.15 and 5.14 eV, respectively, due to intramolecular repulsing between the main chain and side chain as well as the introduction of electron withdrawing side chains. In addition, the introduction of bithiophene into the repeating unit of PSTTOBT showed increased long wave absorption and better intermolecular interaction. PSTTO and PSTTOBT based cell showed power conversion efficiencies of 1.1% and 1.6%, respectively.

31.2: Invited Paper: High Efficiency Red and Green InP‐Quantum Dot Light‐Emitting Diodes

We demonstrate high‐efficiency red and green indium phosphide (InP) quantum dot light‐emitting diodes (QLEDs) comprising low mobility electron transport layer and high mobility hole transport layer with deep HOMO level. Red and green InP‐QLEDs show maximum external quantum efficiency of 21.8% and 13.5%, respectively, and high device stability.

Influence of thiophene and furan π–bridge on the properties of poly(benzodithiophene-alt-bis(π–bridge)pyrrolopyrrole-1,3-dione) for organic solar cell applications

A new polymer, P(BDT-fPPD), which incorporates 4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-bʹ]dithiophene (BDT) and 4,6-bis(furan-2-yl)-2,5-dioctylpyrrolo [3,4-c]pyrrole-1,3(2H,5H)-dione (fPPD, furan π–bridged PPD) units, was prepared. The optoelectrical, crystalline, charge transport, backbone curvature, and photovoltaic properties of P(BDT-fPPD) were thoroughly studied. P(BDT-fPPD) was also compared to the polymer P(BDT-tPPD), comprising BDT and 4,6-bis(thiophen-2-yl)-2,5-dioctylpyrrolo [3,4-c]pyrrole-1,3(2H,5H)-dione (tPPD, thiophene π–bridged PPD) units. This study demonstrates that the π–bridges, such as thiophene and furan, attached between the BDT and pyrrolo [3,4-c]pyrrole-1,3(2H,5H)-dione (PPD) units greatly altered the properties of the resulting polymers. In particular, the backbone curvature of P(BDT-fPPD) was significantly different from that of P(BDT-tPPD), which resulted in P(BDT-fPPD) having a higher bandgap energy (Eg), deeper HOMO level, and higher crystallinity, but lower carrier mobility (μh) and relatively poor power conversion efficiency (PCE) compared to P(BDT-tPPD). For P(BDT-fPPD), the Eg, HOMO, μh, and PCE were determined as 2.20 eV, −5.44 eV, 1.19 × 10−5 cm−2 V−1 s−1, and 2.62%, respectively. The corresponding values for P(BDT-tPPD) were 2.11 eV, −5.39 eV, 2.95 × 10−4 cm−2 V−1 s−1 and 5.29%, respectively. Interestingly, the inclusion of a small amount of P(BDT-tPPD) in the PTB7-Th:PC70BM blend enhanced the PCE of the resulting ternary organic solar cells (OSCs), whereas the insertion of P(BDT-fPPD) lowered the PCE of the ternary OSCs. The lower mobility and PCE obtained for P(BDT-fPPD) are mainly attributed to its poor blending with PC70BM.

Synthesis, spectroscopic, electrochemical and photophysical properties of high band gap polymers for potential applications in semi-transparent solar cells

BackgroundThe design of new polymers able to filter the electromagnetic spectrum and absorb distinctly in the UV and high-energy part of visible spectrum is crucial for the development of semi-transparent solar cells. Herein, we report on the synthesis and spectroscopic, electrochemical, and photophysical characteristics of three new polymers, namely (i) Poly(triamterene-co-terephthalate), (ii) Poly[triamterene-co- 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-p,p′-disulfonamide], and (iii) Poly(5-hydroxyindole-2-carboxylate) that might show promise as materials for semi-transparent solar cells.ResultsThe energy band gap, refractive index, dielectric constant, and optical conductivity of the electron donor polymer, poly(triamterene-co-terephthalate), were determined to be 2.92 eV, 1.56, 2.44 and 2.43 × 104 S cm−1, respectively. The synthesized electron acceptor polymers showed a relatively high refractive index, dielectric constant, and optical conductivity. The presence of a direct allowed transition was confirmed between intermolecular energy bands of the polymers.ConclusionsThe polymers showed relatively high energy gap and deep HOMO levels, making them strong absorbers of photons in the UV region and high energy part of the visible region. The synthesized donor and acceptors performed well relative to P3HT and fullerenes due to the close match of the HOMO and LUMO levels. With further development, the polymers could be viable for use as the active layers of semi-transparent solar cells.

Difluoroterthiophene as promising block to build highly planar conjugated polymer for polymer photovoltaic cells

Developing highly planar semiconducting polymer is essential for achieving high mobility and improving the photovoltaic performance of bulk-heterojunction polymer solar cells. In this contribution, two novel low-bandgap donor-acceptor copolymers, P1-3T and P2-3T2F, consisting of electron-accepting benzothiadiazole acceptor segment and electron-donating terthiophene donor segment with and without fluorine atoms were designed and synthesized. The density functional theory calculations and ultraviolet–visible absorption studies demonstrate that the fluorinated P2-3T2F polymer has more planar backbone conformation, deeper HOMO level, broader absorption spectrum with a vibronic shoulder peak, and higher absorption coefficient compared with the non-fluorinated analogue polymer, P1-3T. Furthermore, P2-3T2F exhibits good crystallinity and high hole mobility, presumably due to the well-ordered lamellar packing and the π-π stacking interaction between the backbones of the conjugated polymers. The optimized polymer solar cell based on P2-3T2F:PC61BM exhibits a short-circuit current density (Jsc) of 12.77 mA cm−2, a fill factor (FF) of 68.99%, an open-circuit voltage (Voc) of 0.80 V, and a maximum power conversion efficiency (PCE) of 7.14%, which is approximately 46% higher than that of the P1-3T:PC61BM device. The enhanced PCE is primarily due to increased light-harvesting ability and interconnected morphology with finely dispersed polymer-rich and PC61BM-rich domains, which improves the efficiency of exciton dissociation and rises the mobility of charge carriers, thus boosting the short-circuit current density and the FF value. Moreover, the relatively deep HOMO of P2-3T2F effectively increases the Voc.

Wide-bandgap donor polymers based on a dicyanodivinyl indacenodithiophene unit for non-fullerene polymer solar cells.

A wide-bandgap polymer donor with improved efficiency plays an important role in improving the photovoltaic performance of polymer solar cells (PSCs). In this study, two novel wide-bandgap polymer donors, PBDT and PBDT-S, were designed and synthesized based on a dicyanodivinyl indacenodithiophene (IDT-CN) moiety, in which benzo[1,2-b:4,5-b′]dithiophene (BDT) building blocks and IDT-CN are used as electron-sufficient and -deficient units, respectively. In our study, the PBDT and PBDT-S polymer donors exhibited similar frontier-molecular-orbital energy levels and optical properties, and both copolymers showed good miscibility with the widely used narrow-bandgap small molecular acceptor Y6. Non-fullerene polymer solar cells (NF-PSCs) based on PBDT:Y6 exhibited an impressive power conversion efficiency of 10.04% with an open circuit voltage of 0.88 V, a short-circuit current density of 22.16 mA cm−2 and a fill factor of 51.31%, where the NF-PSCs based on PBDT-S:Y6 exhibited a moderate power conversion efficiency of 6.90%. The enhanced photovoltaic performance, realized by virtue of the improved short-circuit current density, can be attributed to the slightly enhanced electron mobility, higher exciton dissociation rates, more efficient charge collection and better nanoscale phase separation of the PBDT-based device. The results of this work indicate that the IDT-CN unit is a promising building block for constructing donor polymers for high-performance organic photovoltaic cells.

Highly thermal stable electron-transporting materials using triptycene derivatives for OLEDs

Highly thermal stable two-electron transport materials (ETMs) based on the triptycene containing phenylpyridine derivatives were designed and synthesized by Suzuki-Miyaura coupling reactions efficiently. Among them, TPP shows a high triplet energy gap (ET = 2.85 eV), high glass transition temperature (Tg = 142 °C), deep HOMO level (7.0 eV) and good electron mobility. TPP performed as ETM for the green phosphorescent OLED was achieved high external quantum efficiency (EQE) compared to that of the device with TmPyPB as ETM. Moreover, thermal stability was demonstrated after thermal annealing of the device at 100 °C for 30 min, resulting in the TPP-based device reached a high EQE of 13.6% at a luminance of 100 cd m−2, while that of TmPyPB-based device have dramatically degraded under otherwise identical conditions.

Good Charge Balanced Inverted Red InP/ZnSe/ZnS-Quantum Dot Light-Emitting Diode with New High Mobility and Deep HOMO Level Hole Transport Layer

Here, we report efficient and stable indium phosphide (InP) based inverted red quantum dot light-emitting diodes (QLEDs) using a new high mobility and deep HOMO level hole transport layer (HTL) and...

Functional Third Components in Nonfullerene Acceptor-Based Ternary Organic Solar Cells

ConspectusNonfullerene acceptors (NFAs) represent the latest breakthrough in organic solar cells (OSCs), which significantly outperform the long benchmark OSCs with fullerene derivative acceptors. In addition to binary bulk heterojunction (BHJ) OSCs, multicomponent, in particular ternary BHJ strategy has attracted tremendous interests due to the realization of broadened coverage of solar spectrum while maintaining easy processing compared to tandem OSCs. Subsequently, ternary OSCs containing NFA(s) have provided exciting opportunities to the promising field and achieved great progress in power conversion efficiencies (PCEs) over 17%. Inspired by the recent progress, in this account, we focus on the ternary OSCs containing NFA(s), share our view of the topic and aim to provide guidelines for material selections in designing successful ternary OSCs—toward the cornerstone of 20% PCE in the near future.In this Account, we first discuss the principle of OSCs—working mechanisms, including charge transfer and energy transfer that govern the charge dynamics. Moreover, the promising functional roles of the third components in NFA OSCs are highlighted at the following the sequence: (1) Absorption sensitizing—the additional component plays a key role in broadening the solar cell absorption window and thus promising in improving the photocurrent in the ternary active layer, especially when employing a near-infrared material NFA as the third component. (2) Morphology manipulation approaches and models—the ternary blend nanostructure is complex and not trivial to understand. Parallel and alloy nanomorphology models are discussed on the basis of the simultaneous consideration of the intrinsic properties among the involved materials, such as electronic properties and interplay (miscibility) among the host–guest materials. (3) Energy loss management—the addition of donor or acceptor with small energy loss, especially low bandgap material, as the third component holds the promises to reduce the energy loss in ternary OSCs. On the other hand, due to the advantage of the alloyed microstructure in precisely tuning VOC, applying a second donor with deeper HOMO level or a second acceptor with shallower LUMO level is expected to increase VOC and thus reduce the energy loss in ternary OSCs. (4) Stability boosting agent—from the thermodynamic point of view, the stable BHJ microstructure is beneficial and critical in enhancing the OSCs’ long-term thermal and light stability. However, most material combinations suffer from the poor miscibility between the donor phase and acceptor phase, leading to demixing of two phases and thus the performance degradation. On the basis of this concept, rational selection of the third component could facilitate the formation of glassy nanostructure by vitrifying the pure donor phase or acceptor phase. Also it worth noting that suppressed crystallization of the small molecular acceptors by mixing a miscible component is effective to achieve a stable morphology. At the end of the Account, we share our view on the issues that limit the performance of ternary OSCs and outline their perspectives.