Polymeric Hole Transport Materials Research Articles

Dopant-Free Bithiophene-Imide-Based Polymeric Hole-Transporting Materials for Efficient and Stable Perovskite Solar Cells.

The development of hole-transport materials (HTMs) with high mobility, long-term stability, and comprehensive passivation is significant for simultaneously improving the efficiency and stability of perovskite solar cells (PVSCs). Herein, two donor-acceptor (D-A) conjugated polymers PBTI and PFBTI with alternating benzodithiophene (BDT) and bithiophene imide (BTI) units are successfully developed with desirable hole mobilities due to the good planarity and extended conjugation of molecular backbone. Both copolymers can be employed as HTMs with suitable energy levels and efficient defect passivation. Shortening the alkyl chain of the BTI unit and introducing fluorine atoms on the BDT moiety effectively enhances hole mobility and hydrophobicity of the HTMs, leading to improved efficiency and stability of PVSCs. As a result, the organic-inorganic hybrid PVSCs with PFBTI as the HTM deliver a power conversion efficiency (PCE) of 23.1% with enhanced long-term operational and ambient stability, which is one of the best efficiencies reported for PVSCs with dopant-free polymeric HTMs to date. Moreover, PFBTI can be applied in inorganic PVSCs and perovskite/organic tandem solar cells, achieving a high PCE of 17.4% and 22.2%, respectively. These results illustrate the great potential of PFBTI as an efficient and widely applicable HTM for cost-effective and stable PVSCs.

Molecular Design of Diazo Compound for Carbene-Mediated Cross-Linking of Hole-Transport Polymer in QLED with Reduced Energy Barrier and Improved Charge Balance.

Polymeric hole-transport materials (HTMs) have been widely used in quantum-dot light-emitting diodes (QLEDs). However, their solution processability normally causes interlayer erosion and unstable film state, leading to undesired device performance. Besides, the imbalance of hole and electron transport in QLEDs also damages the device interfaces. In this study, we designed a bis-diazo compound, X1, as carbene cross-linker for polymeric HTM. Irradiated by ultraviolet and heating, a poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt(4,4'-(N-(4-butylphenyl))] (TFB)/X1 blend can achieve fast "electronically clean" cross-linking with ∼100% solvent resistance. The cross-linking reduced the stacking behaviors of TFB and thus led to a lower hole-transport mobility, whereas it was a good match of electron mobility. The carbene-mediated TFB cross-linking also downshifted the HOMO level from -5.3 to -5.5 eV, delivering a smaller hole-transport energy barrier. Benefiting from these, the cross-linked QLED showed enhanced device performances over the pristine device, with EQE, power efficiency, and current efficiency being elevated by nearly 20, 15, and 83%, respectively. To the best of our knowledge, this is the first report about a bis-diazo compound based carbene cross-linker built into a polymeric HTM for a QLED with enhanced device performance.

A Multifunctional Fluorinated Polymer Enabling Efficient MAPbI3-Based Inverted Perovskite Solar Cells.

Exploring polymeric hole-transporting materials (HTMs) with passivation functions represents a simplified and effective approach to minimize the perovskite defect density. To date, most of reported polymeric HTMs were applied to fabricate n-i-p regular perovskite solar cells (PSCs). The polymers compatible for p-i-n inverted PSCs were very limited. Moreover, the passivation polymers were devoted to passivate the uncoordinated Pb2+. However, the MA+ cation defect has profound unwanted effect on device efficiency and long-term stability. In order to synchronously passivate the Pb2+ and MA+ defects in p-i-n inverted PSCs, a new nonfused polymer was intentionally explored via mild polymerization. The aromatic bridge instead of long alkyl chains enabled polymer BN-12 to achieve excellent thermal stability and good wettability of perovskite precursor. Furthermore, the incorporation of chemical anchor sites ("C═O" and "F") strongly controlled the crystallization of perovskite and restrained the MA+ ion migration. As a result, a significant fill factor (FF) of 82.9% and an enhanced power conversion efficiency (PCE) of 20.28% were achieved for MAPbI3-based devices with the dopant-free BN-12, exceeding those with the commercial HTM PTAA (FF = 81.7%, PCE = 19.51%). More importantly, the unencapsulated devices based on BN-12 realized outstanding long-term stability, maintaining approximately 95% of its initial efficiency after stored for 85 days. By contrast, the PTAA-based device showed rapid decrease which retained only 50% of its initial value after 45 days.

Tailored Polymeric Hole-Transporting Materials Inducing High-Quality Crystallization of Perovskite for Efficient Inverted Photovoltaic Devices.

For achieving high-performance p-i-n perovskite solar cells (PSCs), hole transporting materials (HTMs) are critical to device functionality and represent a major bottleneck to further enhancing device stability and efficiency in the inverted devices. Three dopant-free polymeric HTMs are developed based on different linkage sites of triphenylamine and phenylenevinylene repeating units in their main backbone structures. The backbone curvatures of the polymeric HTMs affect the morphology and hole mobility of the polymers and further change the crystallinity of perovskite films. By using PTA-mPV with moderate molecular curvature, p-i-n PSCs with high efficiency of 19.5% and long-term stability can be achieved. The better performance is attributed to the more effective hole extraction ability, higher charge-carrier mobility, and lower interfacial charge recombination. Furthermore, these three polymeric HTMs are synthesized without any noble metal catalyst, and show great advantages in future application owing to the low-cost.

Pyrene-Based Dopant-Free Hole-Transport Polymers with Fluorine-Induced Favorable Molecular Stacking Enable Efficient Perovskite Solar Cells.

A new class of polymeric hole‐transport materials (HTMs) are explored by inserting a two‐dimensionally conjugated fluoro‐substituted pyrene into thiophene and selenophene polymeric chains. The broad conjugated plane of pyrene and “Lewis soft” selenium atoms not only enhance the π–π stacking of HTM molecules greatly but also render a strong interaction with the perovskite surface, leading to an efficient charge transport/transfer in both the HTM layer and the perovskite/HTM interface. Note that fluorine substitution adjacent to pyrene boosts the stacking of HTMs towards a more favorable face‐on orientation, further facilitating the efficient charge transport. As a result, perovskite solar cells (PSCs) employing PE10 as dopant‐free HTM afford an excellent efficiency of 22.3 % and the dramatically enhanced device longevity, qualifying it among the best PSCs based on dopant‐free HTMs.

Simple-Structured Low-Cost Dopant-Free Hole-Transporting Polymers for High-Stability CsPbI2Br Perovskite Solar Cells.

Among the solution-processed devices, perovskite solar cells (PSCs) exhibit the highest power conversion efficiency (PCE) of over 25%; tremendous efforts are being undertaken to improve their stability. Recently, all-inorganic CsPbI2Br-based PSCs were reported to exhibit a significantly improved device stability, with a promising PCE of up to 16.79%. In this study, we report stable all-inorganic PSCs by incorporating novel dopant-free hole-transporting materials (HTMs). The synthesis strategy of the newly synthesized polymeric HTMs was similar to that of 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD), with the exception that they were designed to exhibit dopant-free characteristics. In particular, their polymeric backbone structure was significantly simpler than that of spiro-OMeTADs, and they were easily synthesized in two steps from commercially available chemicals, with an overall yield of ∼50%. The cost of synthesis at the laboratory scale was calculated to be at least 2.4 times cheaper than that of spiro-OMeTADs. The PCE of dopant-free HTM-based PSCs was 11.01%, which is 1.5 times higher than that of the dopant-free spiro-OMeTAD-based devices (7.52%) and comparable to that of the doped spiro-OMeTAD-based devices (12.22%). Notably, the stability of the device based on our dopant-free HTM to atmospheric oxygen and moisture as well as heat and light irradiation was superior to that of devices based on doped and dopant-free spiro-OMeTAD HTMs. On consideration of the synthesis cost, device efficiency, and device stability, our dopant-free HTM is highly promising for all-inorganic PSCs.

Dopant-free, hole-transporting polymers containing benzotriazole acceptor unit for perovskite solar cells

Dopant-free, electron donor (D)–acceptor (A) type, polymeric hole-transporting materials (HTMs) possess excellent film formability and hole transport properties, which ensure high efficiency, stability, and reproducibility to the PVSCs. Compared with benzothiadiazole (BT), benzotriazole (BTA) was less incorporated into polymeric HTMs. Herein, two indacenodithieno[3,2-b]thiophene (IDTT)-BTA copolymers BT-T and BT-TT containing different π-bridge of thiophene and thienothiophene, are synthesized and studied. BT-T bearing thiophene π-bridge presents decent coplanarity, higher hole mobility, and better interface morphology than its sister polymer BT-TT. The PVSC with dopant-free BT-T displayed a peak power conversion efficiency (PCE) of 17.1% and remained above 85% of its initial PCE for more than 30 days at ambient conditions. In view of the rare report on the BTA-based polymeric HTMs, this work will cast lights on further exploration of high-efficiency D-A polymeric HTMs.

A Phenanthrocarbazole-Based Dopant-Free Hole-Transport Polymer with Noncovalent Conformational Locking for Efficient Perovskite Solar Cells.

Adequate hole mobility is the prerequisite for dopant-free polymeric hole-transport materials (HTMs). Constraining the configurational variation of polymer chains to afford a rigid and planar backbone can reduce unfavorable reorganization energy and improve hole mobility. Herein, a noncovalent conformational locking via S-O secondary interaction is exploited in a phenanthrocarbazole (PC) based polymeric HTM, PC6, to fix the molecular geometry and significantly reduce reorganization energy. Systematic studies on structurally explicit repeats to targeted polymers reveals that the broad and planar backbone of PC remarkably enhances π-π stacking of adjacent polymers, facilitating intermolecular charge transfer greatly. The inserted "Lewis soft" oxygen atoms passivate the trap sites efficiently at the perovskite/HTM interface and further suppress interfacial recombination. Consequently, a PSC employing PC6 as a dopant-free HTM offers an excellent power conversion efficiency of 22.2 % and significantly improved longevity, rendering it as one of the best PSCs based on dopant-free HTMs.

A Phenanthrocarbazole‐Based Dopant‐Free Hole‐Transport Polymer with Noncovalent Conformational Locking for Efficient Perovskite Solar Cells

AbstractAdequate hole mobility is the prerequisite for dopant‐free polymeric hole‐transport materials (HTMs). Constraining the configurational variation of polymer chains to afford a rigid and planar backbone can reduce unfavorable reorganization energy and improve hole mobility. Herein, a noncovalent conformational locking via S–O secondary interaction is exploited in a phenanthrocarbazole (PC) based polymeric HTM, PC6, to fix the molecular geometry and significantly reduce reorganization energy. Systematic studies on structurally explicit repeats to targeted polymers reveals that the broad and planar backbone of PC remarkably enhances π–π stacking of adjacent polymers, facilitating intermolecular charge transfer greatly. The inserted “Lewis soft” oxygen atoms passivate the trap sites efficiently at the perovskite/HTM interface and further suppress interfacial recombination. Consequently, a PSC employing PC6 as a dopant‐free HTM offers an excellent power conversion efficiency of 22.2 % and significantly improved longevity, rendering it as one of the best PSCs based on dopant‐free HTMs.

Donor–Acceptor Type Polymer Bearing Carbazole Side Chain for Efficient Dopant‐Free Perovskite Solar Cells

AbstractIn conventional n–i–p perovskite solar cells (PVSCs), electron donor (D)–acceptor (A) polymers have been found to be potential substitutes for doped spiro‐based small molecule hole‐transporting materials (HTMs) due to their excellent performance in hole mobility, film formability, and stability. Herein, a benzo[1,2‐b:4,5‐b′]dithiophene (BDT)‐benzodithiophene‐4,8‐dione (BDD) copolymer PBDB‐Cz is developed by employing carbazole as the conjugated side chain of BDT. PBDB‐O and PBDB‐T with alkoxy and thiophene as the side chain of BDT, respectively, are also synthesized and studied for comparison. The synergistic effect of the carbazole side chain and the BDT‐BDD backbone to promote hole transport properties is found in PBDB‐Cz. The carbazole side chain enhances both coplanarity and interaction of polymer chains, while simultaneously deepening energy levels and improving the hole mobility of the polymeric HTM. Consequently, PBDB‐Cz outperforms two counterparts, exhibiting a promising power conversion efficiency (PCE) of 22.06%. Notably, the PBDB‐Cz also improves the device stability, and the devices can retain more than 90% of their initial PCEs after being stored at ambient conditions for 100 days. To the best of the authors’ knowledge, this is the first report to incorporate carbazole into D–A polymeric HTM by side chain engineering.

Stable perovskite solar cells with efficiency of 22.6% via quinoxaline-based polymeric hole transport material

Stable perovskite solar cells with efficiency of 22.6% via quinoxaline-based polymeric hole transport material

Dopant-free polymer/2D/3D perovskite solar cells with high stability

Dopant-free hole transporting materials (HTMs) are promising to tackle the stability issue of perovskite solar cells (PSCs) compared to traditional ones requiring hygroscopic additives. In addition to developing more dopant-free HTMs and increasing their hole extraction/transport ability, interfacial issues between perovskite and dopant-free HTM also remarkably impact on the PSC performance, which, however, have been less concerned. Herein, we introduce a 2D perovskite layer to the interface of 3D perovskite and a dopant-free polymeric HTM to improve the device efficiency and stability. The 2D perovskite layer can increase hole transports by offering a gradient energy-level alignment, decrease defects density, and improve contact at the interface, which are more efficiently when the 2D perovskite is prepared from a fluorine-containing organic cation. Accordingly, a device efficiency of 20.5% is obtained, quite impressive for dopant-free HTM-based 2D–3D PSCs. In particular, these devices without encapsulation exhibit excellent stability under high humidity (85%), heating (80 °C), or light illumination (1-sun), ascribed to double protections from both 2D perovskite layer and dopant-free polymer. This work offers a promising method to enhance the efficiency and stability of dopant-free HTM-based PSCs by introducing a 2D perovskite layer at the interface.

Dopant‐Free Ternary Conjugated Polymeric Hole‐Transporting Materials for Efficient Inverted Planar Perovskite Solar Cells

In inverted perovskite solar cells (PSCs), hole transport materials (HTMs) can efficiently improve hole extraction and transfer as well as the crystallization of perovskite films and thus enhance the photovoltaic performance. Herein, two dopant‐free, regular A1–D–A2–D‐type (D: electron donor; A: electron acceptor) polymeric HTMs, PTPDTBT and PDPPTBT, are developed by integrating the benzothiadiazole unit (A1) with the electron‐accepting species of either a thieno[3,4‐c]pyrrole‐4,6‐dione or a pyrrolo[3,4‐c]pyrrole‐1,4‐dione segment (A2), respectively, where the thiophene unit (D) results in a kinked molecular geometry. These A1–D–A2–D‐type terpolymers exhibit comparable nonpolar properties but distinct film‐quality morphology and charge transport characteristics. PDPPTBT with the more insulating side‐chain groups is found to improve the quality of perovskite films cast on top with larger grain sizes and more homogeneous crystallization. As a consequence, the PDPPTBT‐based PSCs without any dopants and additional interlayers display a champion power conversion efficiency of 18.17%, one of the highest values of MAPbI3‐based inverted PSCs using dopant‐free D‐A‐type polymeric HTMs. Furthermore, the PDPPTBT‐based device exhibits negligible hysteresis and high long‐term stability. This work provides a potential strategy to design dopant‐free A1–D–A2–D‐type polymeric HTMs for efficient and stable PSCs.

Dopant-free hole transporting polymeric materials based on pyrroloindacenodithiophene donor unit for efficient perovskite solar cells

The hole transporting materials (HTMs) have been extensively studied since the HTMs play a critical role in promoting charge extraction/transport and reducing charge recombination between the perovskite layer and the top metal electrode, thus improving the device power conversion efficiency (PCE). In this study, novel polymeric HTMs with pentacyclic pyrroloindacenodithiophene (NIDT) as an electron-rich unit, and electron-deficient benzotriazole (BTA) as an acceptor, labelled as SGT-512 and SGT-513, were designed and synthesized. To regulate the electron withdrawing ability of the acceptor part, two thiophene units were introduced to the BTA moiety as an acceptor, yielding SGT-513 with a slightly raised HOMO energy level. The alkyl side-chain was introduced to the fused BTA unit to improve the solubility and regulate the morphology and stacking behavior of HTM. Meanwhile, for the donor part, the replacement of the bridging heteroatom in indacenodithiophene with the more electron donating nitrogen atom, helped to promote molecular orbital hybridization leading to a narrower bandgap polymer. The combination of the features of the NIDT donor and BTA acceptor enabled the production of the D-A type polymeric HTM SGT-512 with a high intrinsic hole mobility of 3.8 × 10−4 cm2V−1s−1, a suitable HOMO energy level (−5.25 eV) corresponding to the valence band of the perovskite layer, and excellent film-formation ability. Therefore, the PrSCs based on dopant-free SGT-512 showed a high PCE of 15.57%, which is much higher than that of the control device based on dopant free-P3HT, with a PCE of 13.52%.

Dopant-free hole-transporting polymers for efficient, stable, and hysteresis-less perovskite solar cells

Four novel polymers have been investigated as promising solution processable, dopant-free polymeric hole-transporting materials (HTMs) for efficient and stable perovskite solar cells. The poly(1-(4-hexylphenyl)-2,5-bis(5-methylthiophen-2-yl)-1H-pyrrole) p(hPhDTP), poly(1-(4-methoxyphenyl)-2,5-bis(5-methylthiophen-2-yl)-1H-pyrrole)p(mPhDTP), poly(3-hexyl-5,5′-dimethyl-2,3′-bithiophene) p(hBT) and poly(5,5′-dimethyl-2,3′-bithiophene) p(BT) HTMs have successfully been synthesized from relatively cheap raw materials with a facile synthetic route. The fabricated polymers are potentially cost-effective and exhibit favourable HOMO level with respect to the valence band of the perovskite active layer. The incorporation of the new HTMs in the perovskite solar cell architecture exhibited excellent overall power conversion efficiency (PCE) of 16.20, 14.45, 11.10 and 9.63% for P(hPhDTP), P(mPhDTP), P(hBT), and P(BT), respectively with minimal hysteresis without the use of any dopants or additives, which is higher than the 8.33% obtained using P3HT-based devices. The high efficiency can be attributed to the positive HOMO energy level and the high hole (h+) mobility. In addition, the long-term stability of the polymers as HTM devices were studied, where they maintained their initial efficiency for over 1200 h, whereas devices made using P3HT as HTM drops down to almost half of its value after 600 h.

Conformational and Compositional Tuning of Phenanthrocarbazole-Based Dopant-Free Hole-Transport Polymers Boosting the Performance of Perovskite Solar Cells.

Conjugated polymers are regarded as promising candidates for dopant-free hole-transport materials (HTMs) in efficient and stable perovskite solar cells (PSCs). Thus far, the vast majority of polymeric HTMs feature structurally complicated benzo[1,2-b:4,5-b’]dithiophene (BDT) analogs and electron-withdrawing heterocycles, forming a strong donor–acceptor (D–A) structure. Herein, a new class of phenanthrocarbazole (PC)-based polymeric HTMs (PC1, PC2, and PC3) has been synthesized by inserting a PC unit into a polymeric thiophene or selenophene chain with the aim of enhancing the π–π stacking of adjacent polymer chains and also to efficiently interact with the perovskite surface through the broad and planar conjugated backbone of the PC. Suitable energy levels, excellent thermostability, and humidity resistivity together with remarkable photoelectric properties are obtained via meticulously tuning the conformation and elemental composition of the polymers. As a result, PSCs containing PC3 as dopant-free HTM show a stabilized power conversion efficiency (PCE) of 20.8% and significantly enhanced longevity, rendering one of the best types of PSCs based on dopant-free HTMs. Subsequent experimental and theoretical studies reveal that the planar conformation of the polymers contributes to an ordered and face-on stacking of the polymer chains. Furthermore, introduction of the “Lewis soft” selenium atom can passivate surface trap sites of perovskite films by Pb–Se interaction and facilitate the interfacial charge separation significantly. This work reveals the guiding principles for rational design of dopant-free polymeric HTMs and also inspires rational exploration of small molecular HTMs.

A Ladder-like Dopant-free Hole-Transporting Polymer for Hysteresis-less High-Efficiency Perovskite Solar Cells with High Ambient Stability.

Perovskite solar cells (PSCs) have received high attention in the past few years due to their terrific photovoltaic performance and potentially low production cost. However, the use of hole transport materials (HTMs) with hygroscopic dopants, which cause the inevitable instability of device performance, has hampered commercialization. Herein, a dopant-free polymeric HTM with functional aromatic rings was used to optimize the HTM/perovskite interface and employed in a planar n-i-p configuration. Poly(1,4-(2,5-bis((2-butyloctyloxy)phenylene)-2,7-(5,5,10,10-tetrakis(4-hexylphenyl)-5,10-dihydro-s-indaceno[2,1-b:6,5-b']dithiophene)) (IDTB) co-polymer constructed with indaceno[1,2-b:5,6-b']dithiophene and bis(alkyloxy)benzene units adopts an S⋅⋅⋅O intramolecular bond linked ladder-like planar conjugated polymer backbone. Without any dopant, the hole mobility of IDTB is in the same order of magnitude as a doped 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (spiro-OMeTAD). Also, the hydrophobic nature of IDTB facilitated the long-term stability of the perovskite underneath. The unencapsulated PSC devices made of IDTB-based HTM achieved a power conversion efficiency of 19.38 % with a high moisture stability, retaining above 80 % of initial power conversion efficiency at 65 % relative humidity for more than 10 days. The superior passivation effect to perovskite surface made a hysteresis of 0.44 % was almost the least reported for regular planar undoped polymer HTM PSCs.

Development of Dopant‐Free Organic Hole Transporting Materials for Perovskite Solar Cells

AbstractThere has been considerable progress over the last decade in development of the perovskite solar cells (PSCs), with reported performances now surpassing 25.2% power conversion efficiency. Both long‐term stability and component costs of PSCs remain to be addressed by the research community, using hole transporting materials (HTMs) such as 2,2′,7,7′‐tetrakis(N,N′‐di‐pmethoxyphenylamino)‐9,9′‐spirbiuorene(Spiro‐OMeTAD) and poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine] (PTAA). HTMs are essential for high‐performance PSC devices. Although effective, these materials require a relatively high degree of doping with additives to improve charge mobility and interlayer/substrate compatibility, introducing doping‐induced stability issues with these HTMs, and further, additional costs and experimental complexity associated with using these doped materials. This article reviews dopant‐free organic HTMs for PSCs, outlining reports of structures with promising properties toward achieving low‐cost, effective, and scalable materials for devices with long‐term stability. It summarizes recent literature reports on non‐doped, alternative, and more stable HTMs used in PSCs as essential components for high‐efficiency cells, categorizing HTMs as reported for different PSC architectures in addition to use of dopant‐free small molecular and polymeric HTMs. Finally, an outlook and critical assessment of dopant‐free organic HTMs toward commercial application and insight into the development of stable PSC devices is provided.

Hole transporting materials for perovskite solar cells: molecular versus polymeric carbazole-based derivatives

Designing organic hole transporting materials (HTMs) for stable perovskite photovoltaic devices remains a great challenge. Herein, we have prepared two small carbazole-based HTMs bearing a polymerizable double bond and one of the corresponding polymers. All compounds can be easily synthetized by a short procedure from largely available commercial products. These compounds have thermal, morphological, optical and electrochemical properties suitable for an application in perovskite solar cells. The side chains at the N-position on the carbazole have a negligible influence on the opto-electrochemical properties. However, the thermal properties differ largely between the monomer and its corresponding polymer. While these materials have the same photovoltaic performance, the polymeric HTM led to more stable devices. This illustrates the higher thermal stability of polymeric HTM versus its corresponding monomer.

Investigating ultrafast carrier dynamics in perovskite solar cells with an extended π-conjugated polymeric diketopyrrolopyrrole layer for hole transportation.

Here, we show a new diketopyrrole based polymeric hole-transport material (PBDTP-DTDPP, (poly[[2,5-bis(2-hexyldecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo[3,4-c]pyrrole-1,4-diyl]-alt-[[2,2′-(4,8-bis(4-ethylhexyl-1-phenyl)-benzo[1,2-b:4,5-b′]dithiophene)bis-thieno[3,2-b]thiophen]-5,5′-diyl]])) for application in perovskite solar cells. The material performance was tested in a solar cell with an optimized configuration, FTO/SnO2/perovskite/PBDTP-DTDPP/Au, and the device showed a power conversion efficiency of 14.78%. The device charge carrier dynamics were investigated using transient absorption spectroscopy. The charge separation and recombination kinetics were determined in a device with PBDTP-DTDPP and the obtained results were compared to a reference device. We find that PBDTP-DTDPP enables similar charge separation time (<∼4.8 ps) to the spiro-OMeTAD but the amount of nongeminate recombination is different. Specifically, we find that the polymeric PBDTP-DTDPP hole-transport layer (HTL) slows-down the second-order recombination much less than spiro-OMeTAD. This effect is of particular importance in studying the charge transportation in optimized solar cell devices with diketopyrrole based HTL materials.