Diindenoperylene Research Articles

Adsorption Structures Affecting the Electronic Properties and Photoinduced Charge Transfer at Perylene-Based Molecular Interfaces.

Perylene-based organic semiconductors are widely used in organic electronic devices. Here, we studied the ultrafast excited state dynamics after optical excitation at interfaces between the electron donor (D) diindenoperylene (DIP) and the electron acceptor (A) dicyano-perylene-bis(dicarboximide) (PDIR-CN2 ) using femtosecond time-resolved second harmonic generation (SHG) in combination with large scale quantum chemical calculations. Thereby, we varied in bilayer structures of DIP and PDIR-CN2 the interfacial molecular geometry. For an interfacial configuration which contains a edge-on geometry but also additional face-on domains an optically induced charge transfer (CT) is observed, which leads to a pronounced increase of the SHG signal intensity due to electric field induced second harmonic generation. The interfacial CT state decays within 7.5±0.7 ps, while the creation of hot CT states leads to a faster decay (5.3±0.2 ps). For the bilayer structures with mainly edge-on geometries interfacial CT formation is suppressed since π-π overlap perpendicular to the interface is missing. Our combined experimental and theoretical study provides important insights into D/A charge transfer properties, which is needed for the understanding of the interfacial photophysics of these molecules.

Simultaneous measurement of X-ray scattering and photoluminescence during molecular deposition

We present a simultaneous in situ measurement of X-ray scattering and photoluminescence (PL) spectroscopy during organic thin-film growth in a vacuum. We have designed a modified deposition chamber that broadens its utilization and enables complementary information on the structure and optoelectronic properties. In a pilot experiment, we investigated the growth of diindenoperylene (DIP) thin films in real time. We found a direct correlation between PL and grazing-incidence wide-angle X-ray scattering (GIWAXS), showing the formation of a new DIP polymorph starting at a layer thickness of ∼14 nm. Furthermore, we show that the PL signal is more sensitive to the arrangement of the molecules than GIWAXS in the limit of small layer thicknesses. The presented experimental setup paves the way for performing simultaneous PL and X-ray scattering measurements during the growth of various materials suitable for optoelectronic applications.

Roughness evolution in strongly interacting donor:acceptor mixtures of molecular semiconductors. An in situ, real-time growth study using x-ray reflectivity

The evolution of surface roughness in binary mixtures of the two molecular organic semiconductors (OSCs) diindenoperylene (DIP) as electron-donor and 1, 3, 4, 5, 7, 8-hexafluoro-tetracyano naphthoquinodimethane (F6TCNNQ) as electron-acceptor is studied. We co-deposit DIP and F6TCNNQ in vacuum with varying relative molar content while keeping a molar excess of DIP in order to produce phase-heterogeneous mixtures. The excess DIP phase segregates in pristine crystallites, whereas the remaining mixed phase is constituted by DIP:F6TCNNQ co-crystallites. We calculate the surface roughness as function of film thickness by modelling x-ray reflectivity data acquired in situ and in real-time during film growth. To model the experimental data, two distinct approaches, namely the kinematic approximation and the Parratt formalism, are applied. A comparative study of surface roughness evolution as function of DIP:F6TCNNQ mixing ratio is carried out implementing the Trofimov growth model within the kinematic approximation. Depending on the thickness regime, mixing ratio-specific trends are identified and discussed. To explain them, a growth mechanism for binary heterogeneous mixtures of strongly interacting OSCs is proposed.

Anomalous photoluminescence quenching in DIP/MoS2 van der Waals heterostructure: Strong charge transfer and a modified interface

Due to the fascinating optoelectronic properties of two-dimensional (2D) transition metal dichalcogenides (TMDs) and the flexible nature, vast library, and easy fabrication process of organic molecules, the combination of 2D TMD materials and organic molecules have been gaining enormous attention in recent years. The organic semiconductors can enhance the optoelectronic and improved transport properties by interfacing with atomically thin TMDs through vdW interaction. Here, we investigate the photoluminescence (PL) properties of type-II heterostructure made of monolayer molybdenum disulfide (ML MoS2) and a non-planar Diindenoperylene(DIP) molecules. A drastic quenching of PL intensity nearly 300% is observed with slightly redshift in DIP/MoS2as compared to the PL of isolated MoS2. The observed quenching behavior in DIP/MoS2heterostructure can be explained by the appeared ‘trap – like’ states in density of states (DOS), and suppression of exciton to trion ratio due to electron transfer from the lowest unoccupied molecular orbital (LUMO) level of DIP to the conduction band minima (CBM) of MoS2. Furthermore, the redshift in the PL of heterostructure could be due to weak coupling strength which is ~8 times smaller than that of the energy of A-exciton resonance of individual layers and dielectric screening effect induced by the non-planar DIP based organic layer. The expected strong interaction between the DIP molecule and MoS2 layer due to the permanent dipole moments (significant molecular quadruple moment 8.25D) of DIP molecules is another reason, which may slightly reduce the bandgap and results in red-shift of PL. We observed Raman (A1g phonon mode) is blue-shifted, which is supposed to stiffening due to the non-planar DIP molecule onto ML MoS2. The strong PL quenching behavior of DIP/MoS2heterostructure can be a potential candidate for tailoring the optoelectronic properties of TMDs that may demonstrate for light-harvesting and canserve as the next generation TMD/organic-based photovoltaic applications.

Dibenzo-tetraphenyl diindeno perylene as hole transport layer for high-bandgap perovskite solar cells

Semi-transparent perovskite solar cells have the competitive edge of being employed for building integrated photovoltaics due to their esthetic benefits as light harvesting windows/facades. Perovskites have received considerable attention in recent years as a thin film photovoltaic alternative, that can also be tweaked for its transparency, evolving from potentially high bandgaps that are suited for semi-transparent solar cell fabrication. Due to the existing trade of between the efficiency and transparency of a perovskite solar cell, tuning the band gap can address this by making a bridge between the aforementioned parameters. We report our findings on the use of a wide-bandgap perovskite MAPbBr3, with a rational energetic level hole transport materials based on polycyclic aromatic hydrocarbon molecules that can be a promising alternative class of p-type material. In the present work, DBP (Dibenzo{[f,f′]-4,4′,7,7′-tetraphenyl}diindeno[1,2,3-cd :1′,2′,3′-lm]perylene was evaluated with high bandgap as well as with mixed (FAPbI3)0.85(MAPbBr3)0.15 perovskites for the fabrication of solar cell. DBP-based solar cells yielded competitive power conversion efficiencies as compared with classical HTMs.

Crystalline versus Amorphous Donor-Acceptor Blends: Influence of Layer Morphology on the Charge-Transfer Density of States

Organic small molecule solar cells are used as a test bed to investigate the influence of film morphology on the density of charge-transfer (CT) states. CT states are considered as precursors for charge generation and their energy as the upper limit for the open-circuit voltage in organic donor-acceptor solar cells. In this study the influence of morphology for two perylene donors [crystalline diindenoperylene (DIP) versus amorphous tetraphenyldibenzoperiflanthene (DBP)] with almost identical ionization energy is investigated. As acceptor material, the fullerene ${\mathrm{C}}_{60}$ is used. By combining device measurements with optical and low-energy ultraviolet photoelectron spectroscopy, a comprehensive picture is obtained that describes how morphology and the connected density of states (DOS) affect device performance and the spectroscopic signature of CT states. Especially for the crystalline donor material DIP, strong exponential tail states reaching far into the gap are observed, which can be related to the presence of grain boundaries. A voltage-dependent filling of these states is identified as the origin of a blue shift of electroluminescence spectra with increasing applied voltage. Different approaches are compared to study the influence of static and dynamic disorder in the description of CT emission and absorption spectra of organic solar cells. Despite the fact that both donors yield almost identical CT energy (and, thus, the same open-circuit voltage) the Stokes shift between photocurrent and electroluminescence spectra and, concomitantly, the width of the CT DOS varies by more than a factor of 2. We discuss this observation in terms of the donor-acceptor reorganization energy as well as an additional line broadening by static disorder. Remarkably, the more crystalline donor DIP shows a significant deviation from a Marcus-type description, while this is not the case for the amorphous DBP. This highlights the importance of film morphology in organic solar cells.

Reorientation of π-conjugated molecules on few-layer MoS2 films.

Small π-conjugated organic molecules have attracted substantial attention in the past decade as they are considered as candidates for future organic-based (opto-)electronic applications. The molecular arrangement in the organic layer is one of the crucial parameters that determine the efficiency of a given device. The desired orientation of the molecules is achieved by a proper choice of the underlying substrate and growth conditions. Typically, one underlying material supports only one inherent molecular orientation at its interface. Here, we report on two different orientations of diindenoperylene (DIP) molecules on the same underlayer, i.e. on a few-layer MoS2 substrate. We show that DIP molecules adopt a lying-down orientation when deposited on few-layer MoS2 with horizontally oriented layers. In contrast, for vertically aligned MoS2 layers, DIP molecules are arranged in a standing-up manner. Employing in situ and real-time grazing-incidence wide-angle X-ray scattering (GIWAXS), we monitored the stress evolution within the thin DIP layer from the early stages of the growth, revealing different substrate-induced phases for the two molecular orientations. Our study opens up new possibilities for the next-generation of flexible electronics, which might benefit from the combination of MoS2 layers with unique optical and electronic properties and an extensive reservoir of small organic molecules.

Excited-State Dynamics in Perylene-Based Organic Semiconductor Thin Films: Theory Meets Experiment

Perylene-based organic semiconductors are widely used in organic electronic devices. Here, we studied the ultrafast excited-state dynamics in diindenoperylene (DIP) and dicyanoperylene-bis(dicarboximide) (PDIR-CN2) thin films, respectively, after optical excitation using femtosecond (fs) time-resolved second harmonic generation in combination with large scale quantum chemical calculations. In DIP, the initial optical excitation leads to the formation of delocalized excitons, which localize on dimers on a ultrafast time scale of <50–150 fs depending on the excitation energy. In contrast, in PDIR-CN2, the optical excitation directly generates localized excitons on monomers or dimers. In both DIP and PDIR-CN2, localized excitons decay within hundreds of fs into Frenkel-like trap sites. The relaxation to the ground state occurs in DIP on a time scale of 600 ± 110 ps. In PDIR-CN2, this relaxation time is 1 order of magnitude faster (62 ± 1.8 ps). The differences in the exciton formation and decay dynamics in D...

Diindenoperylene thin-film structure on MoS2 monolayer

Research on two-dimensional (2D) atomic crystals is one of the highly progressive topics in (opto)electronics, as the van der Waals (vdW) interactions enable integration of 2D crystals with a broad range of materials. Organic π-conjugated molecules offer new opportunities for creating the so-called “hybrid” vdW heterostructures, in which their anisotropy adds an extra degree of functional possibilities. Moreover, it was found that in the case of organic molecules, the 2D substrate changes the molecular orientation, which in turn can enhance the overall optoelectronic properties. However, the reorientation of the molecules has been until now studied solely on the graphene underlayer that restrained its applicability to a broader range of materials. Here, we study the molecular orientation of diindenoperylene (DIP), a representative of rodlike organic semiconductors, on the MoS2 monolayer. Our results show that DIP forms separate islands on the top of the MoS2 monolayer with lying-down orientation of the molecules. We combine the grazing-incidence X-ray diffraction technique with atomistic simulations to reveal the exact molecular arrangement on the atomically thin underlayer. We also investigate optical absorption spectra for different thicknesses of the DIP layer, as they are of fundamental importance for various applications in organic-based optoelectronics.

Shaping and polarizing fluorescence emission of a polycrystalline organic semiconductor film by plasmonic nanogratings

The fluorescence emission properties of hybrid systems consisting of a one-dimensional gold nanowire grating and an evaporated thin film of the small molecule organic semiconductor diindenoperylene (DIP) are investigated. The optical properties of the metallic systems are dominated by their plasmonic resonances. The spectral positions of the resonances are tuned through the width of the single nanowires. Additionally, the plasmonic gratings show a strong polarization dependency due to their one-dimensionality. In contrast, the pure organic system has a polarization-independent emission between 570 and 900 nm when excited with blue light, whereas no photoluminescence can be detected from the bare plasmonic system for the same illumination conditions. For the hybrid system, the intensity, the shape of the emission spectrum, and the polarization of the emission clearly correlate with the optical properties of the plasmonic nanowires. Depending on the optical properties of the plasmonic system, different emission bands of the organic thin film can be enhanced.

Template-Free Orientation Selection of Rod-Like Molecular Semiconductors in Polycrystalline Films.

Many organic semiconductors (OSCs) feature strong optical anisotropy that can be exploited to increase the efficiency of optoelectronic devices. We demonstrate that for the technologically relevant, rod-like OSCs diindenoperylene (DIP), pentacene (PEN), and α-sexithiophene (6T) deposited on silicon oxide surfaces it is possible to prepare polycrystalline thin films in which the long molecular axis is oriented parallel to the substrate plane in a template-free fashion. In films grown by organic molecular beam deposition at room temperature or higher, the molecules are oriented upright standing (σ-orientation). Instead, the here-presented growth at low temperatures followed by slow annealing up to a temperature near molecular desorption has the effect of "freezing" the molecules with their long axis oriented parallel to the substrate plane (λ-orientation) while conferring them crystalline long-range order. We discuss the huge impact on the optical anisotropy of the films observed as a consequence of the orientation transition. Finally, we propose a mechanism for explaining the achieved λ-orientation, which is stable under environmental conditions.

Thin-Film Texture and Optical Properties of Donor/Acceptor Complexes. Diindenoperylene/F6TCNNQ vs Alpha-Sexithiophene/F6TCNNQ

In this work, two novel donor/acceptor (D/A) complexes, namely, diindenoperylene (DIP)/1,3,4,5,7,8-hexafluoro-tetracyanonaphthoquinodimethane (F6TCNNQ) and alpha-sexithiophene (6T)/F6TCNNQ, are studied. The D/A complexes segregate in form of π–π stacked D/A cocrystals and can be observed by X-ray scattering. The different conformational degrees of freedom of the donor molecules, respectively, seem to affect the thin-film crystalline texture and composition of the D/A mixtures significantly. In equimolar mixtures, for DIP/F6TCNNQ, the crystallites are mostly uniaxially oriented and homogeneous, whereas for 6T/F6TCNNQ, a mostly 3D (isotropic) orientation of the crystallites and coexistence of domains of pristine compounds and D/A complex, respectively, are observed. Using optical absorption spectroscopy, we observe for each of the two mixed systems a set of new, strong transitions located in the near-IR range below the gap of the pristine compounds: such transitions are related to charge-transfer (CT) inter...

Interface-Induced Face-on Orientation of Organic Semiconductors with a Template Layer and Its Application to Vertical-Type Organic Transistors

Molecular orientation to the substrate surface is a fundamental problem in organic semiconductor devices due to the anisotropic nature of optoelectronic properties of organic semiconductors. A face-on molecular orientation with the molecular planes parallel to the substrate, is ideal for out-of-plane charge carrier transport for vertical-type organic transistors where charge carriers flow perpendicularly to the substrate. It is usually difficult to induce the face-on molecular orientation on the substrate where intermolecular interactions are stronger than the molecule–substrate surface interactions. Most of the organic semiconductor materials show an edge-on orientation with the molecular planes vertical to the substrate, which is unsuitable for out-of-plane charge carrier transport. Template layer techniques have been proven to enhance the molecule–substrate surface interactions by inserting template materials between the substrate and organic layer. One of the template materials, perylene 3,4,8,9-tetracarboxylic dianhydride (PTCDA) exceptionally show the face-on orientation on the substrate and act as the template layer due to the π-π interactions between PTCDA and the upper side molecules. It has been known that PTCDA is effective for orientation control of phthalocyanine and its derivatives. However, it is still not clear about templating effect for other materials and vertical carrier transport property of organic semiconductors oriented with PTCDA. In this study, we investigated molecular orientation of various π-conjugated crystalline molecules on PTCDA, and the mechanism of orientation control from the crystal structure view point. We also measured the vertical carrier mobility of the oriented molecules and the performance of vertical-type organic transistors, and revealed the effect of orientation control for vertical carrier transport. Dimethyl-3,4,8,9-perylenedicarboximide (MePTC), copper-phthalocyanine (CuPc), dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT), pentacene, and diindenoperylene (DIP) were deposited on glass substrates by thermal vacuum evaporation after deposition of PTCDA. X-ray diffraction (XRD) measurements were carried out in the out-of-plane configuration to evaluate molecular orientation. In these organic semiconductor molecules, MePTC and CuPc on PTCDA gave a diffraction peak at 27.7° with d-spacing of 3.33 Å corresponding to the distance of π-π stacking, which indicates the face-on orientation of the molecules. DNTT, pentacene, and DIP had no diffraction peaks showing the face-on orientation. The difference of molecular orientation results from molecular packing in the crystal structure. Vertical carrier mobility of MePTC was measured by the space charge limited current (SCLC) technique. The electron mobility improved from 1.3×10-4 cm2/Vs to 4.3×10-4 cm2/Vs due to the face-on orientation control. The MePTC film oriented with PTCDA was applied to the metal base organic transisitor (MBOT) which is one of the vertical-type organic transistors, resulting in higher output current compared to the device without PTCDA.

Laboratory Gas-phase Infrared Spectra of Two Astronomically Relevant PAH Cations: Diindenoperylene, and Dicoronylene,

Abstract The first gas-phase infrared spectra of two isolated astronomically relevant and large polycyclic aromatic hydrocarbon (PAH) cations—diindenoperylene (DIP) and dicoronylene (DC)—in the 530–1800 cm−1 (18.9−5.6 μm) range—are presented. Vibrational band positions are determined for comparison to the aromatic infrared bands. The spectra are obtained via infrared multiphoton dissociation spectroscopy of ions stored in a quadrupole ion trap using the intense and tunable radiation of the free electron laser for infrared experiments (FELIX). DIP+ shows its main absorption peaks at 737 (13.57), 800 (12.50), 1001 (9.99), 1070 (9.35), 1115 (8.97), 1152 (8.68), 1278 (7.83), 1420 (7.04), and 1550 (6.45) cm−1(μm), in good agreement with density functional theory (DFT) calculations that are uniformly scaled to take anharmonicities into account. DC+ has its main absorption peaks at 853 (11.72), 876 (11.42), 1032 (9.69), 1168 (8.56), 1300 (7.69), 1427 (7.01), and 1566 (6.39) cm−1(μm), which also agree well with the scaled DFT results presented here. The DIP+ and DC+ spectra are compared with the prominent infrared features observed toward NGC 7023. This results both in matches and clear deviations. Moreover, in the 11.0–14.0 μm region, specific bands can be linked to CH out-of-plane (oop) bending modes of different CH edge structures in large PAHs. The molecular origin of these findings and their astronomical relevance are discussed.

Interrupted Growth to Manipulate Phase Separation in DIP:C60 Organic Semiconductor Blends

We studied the influence of periodic growth interruptions during co-deposition of diindeno-perylene (DIP) and buckminsterfullerene (C60) in an equimolar mixing ratio. DIP and C60 are known to phase-separate when co-deposited, but the details and in particular the length scales depend on kinetic factors. Using X-ray scattering and atomic force microscopy, we demonstrate that the phase separation mechanism is in fact influenced by growth interruptions, with more pronounced effects if the deposition rates are low. For high deposition rates, growth interruptions have no appreciable effect. We discuss our proof of the concept investigation in the context of the relevant processes and their time scales.

Enhancing light absorption in organic semiconductor thin films by one-dimensional gold nanowire gratings

The interaction of metallic plasmonic nanostructures and organic semiconductor thin films plays a crucial role in engineering light harvesting and energy transfer processes, e.g., for optoelectronic applications. Plasmonic resonances of the metal structures can be used to increase the light emission or absorption of organic molecules. Here small molecules are employed since they can form organic layers with a defined crystalline order and orientation of the transition dipole. Extinction measurements combined with numerical simulations of a hybrid system consisting of a gold nanowire grating and a thin film of diindenoperylene (DIP) are reported. The experimental results are compared to the simulations and indicate an enhanced absorption in the wavelength region corresponding to the transition from the highest occupied molecular orbital to the lowest unoccupied molecular orbital of DIP. This enhancement is found to be related to the localized field enhancement near the individual nanostructures as well as to grating-induced effects. Notably, the hybrid system also exhibits parallel lattice resonances, which have recently been discussed for two-dimensional (2D) gold nanostructure arrays. In this study a hybrid plasmonic-organic small molecule system exhibiting these modes is investigated. The results for this model system show a way to modify the optical properties of plasmonic nanostructures by collective effects to achieve stronger light-matter interaction in a wide range of hybrid plasmonic systems.

Diindenoperylene (DIP) concentration dependent photovoltaic performance and dielectric properties for mixed heterojunctions

To find some intrinsic relevance between the photovoltaic performance and dielectric properties of diindenoperylene (DIP) mixed heterojunctions (MHJs), this work demonstrates both the photovoltaic performance and dielectric characteristic dependence on the DIP concentration. 5wt%-DIP MHJ shows relatively higher performance compared to other MHJs with higher DIP ratio over the range of 5wt%–90wt%. The dielectric constant of blend layers decreases with the DIP ratio, thus results in larger Coulomb capture radius and exciton binding energy, which suppresses the exciton dissociation in MHJs with high DIP ratio. Then, the dielectric characteristic of capacitance-voltage (C-V) in dark and under illumination as well as of capacitance-frequency (C-f) at dc bias of 1.6V for the DIP MHJs were measured. The geometric capacitance of the MHJs extracted from the C-V in dark indicates a positive dependence on the DIP concentration. C-V peak height decreases with the DIP concentration from 0 to 60wt% implies that the hole drift becomes dominated at higher DIP content. The open circuit voltage (VOC) of all the MHJs shows an identical trend with the normalized built-in potential. In dark condition, depletion width (W) gradually decreases with the DIP concentration from 5wt% to 60wt%.W becomes narrower under illumination, ascribed to the increased capacitance from photo-generated charge. The free carrier density (ND) imposes a negative influence on fill factor of MHJs. The extracted electron mobility by C-f characteristic gradually decreases with the DIP ratio.

Ultrafast Excited State Dynamics in Diindenoperylene Films

Diindenoperylene (DIP) is an interesting organic molecular semiconductor as a component in organic solar cells. Here, we studied the ultrafast excited state dynamics of DIP after optical excitation in thin films on sapphire and SiO2 substrates, respectively, using femtosecond (fs) time-resolved second harmonic generation (TR-SHG). Sapphire, an inert and noninteracting substrate, is known to deliver no noteworthily contribution to the SHG-signal; thus, the pure response of DIP to the electronic excitation can be resolved in contrast to the measurements on SiO2. For DIP/sapphire, the initial optical excitation leads to the generation of delocalized excitons, which localize within approximately 100 fs in order to generate singlet molecular excitons (Frenkel excitons) or excitons localized on dimers. These excitons have a lifetime of 470 ± 100 fs. In a subsequent step, they form excimer states, which decay on a time scale of 680 ± 110 ps. For DIP/SiO2, the molecular excitons decay on a faster time scale of 210 ± 95 fs and populate either substrate-mediated trap states or excimer states. The present study provides important insights in the excited states dynamics of DIP on the so far unresolved ultrashort time scale, essential for understanding the photophysics of DIP.

Evidence for Anisotropic Electronic Coupling of Charge Transfer States in Weakly Interacting Organic Semiconductor Mixtures.

We present a comprehensive investigation of the charge-transfer (CT) effect in weakly interacting organic semiconductor mixtures. The donor-acceptor pair diindenoperylene (DIP) and N,N'-bis(2-ethylhexyl)-1,7-dicyanoperylene-3,4/9,10-bis(dicarboxyimide) (PDIR-CN2) has been chosen as a model system. A wide range of experimental methods was used in order to characterize the structural, optical, electronic, and device properties of the intermolecular interactions. By detailed analysis, we demonstrate that the partial CT in this weakly interacting mixture does not have a strong effect on the ground state and does not generate a hybrid orbital. We also find a strong CT transition in light absorption as well as in photo- and electroluminescence. By using different layer sequences and compositions, we are able to distinguish electronic coupling in-plane vs out-of-plane and, thus, characterize the anisotropy of the CT state. Finally, we discuss the impact of CT exciton generation on charge-carrier transport and on the efficiency of photovoltaic devices.

Significant reduction in the hole-injection barrier by the charge-transfer state formation: Diindenoperylene contacted with silver and copper electrodes

Charge-carrier injection in organic electronics is critically influenced by the interface electronic states formed at the organic semiconducting thin films and metal electrode contacts. A practical solution for the issue is to form a charge-transfer (CT) state at the interfaces, which will produce a substantial density of gap states in the vicinity of the Fermi level of metal electrodes and thus reduce significantly the charge-injection barrier at the interfaces. In this study, we use ultraviolet photoelectron spectroscopy and demonstrate the formation of a CT state at diindenoperylene (DIP) and Ag (or Cu) electrode contacts. Remarkably, the CT state occurs irrespective of the electrode crystallinity, crystal grain orientations, or the molecular orientations in the DIP film, hence both the top- or bottom-metal contact conditions result in the formation of the CT state. Theoretical calculation simulations show the sign of strong interaction between those metal atoms and DIP leading to the CT state formation, analogous to the surface-induced aromatic stabilization proposed by Heimel et al. in a literature [Nat. Chem., 5(2013)187.]. Our results aid in understanding the mechanism of the CT state formation and propose the DIP-CT interlayers being novel candidates for the efficient hole-injection layers used in organic electronics.