Interface Dipole Effect Research Articles

Unraveling the Role of Electron‐Withdrawing Molecules for Highly Efficient and Stable Perovskite Photovoltaic

Electron‐withdrawing molecules (EWMs) have exhibited remarkable efficacy in boosting the performance of perovskite solar cells (PSCs). However, the underneath mechanisms governing their positive attributes remain inadequately understood. Herein, we conducted a comprehensive study on EWMs by comparing 2,2'‐(2,5‐cyclohexadiene‐1,4‐diylidene) bismalononitrile (TCNQ) and (2,3,5,6‐tetrafluoro‐2,5‐cyclohexadiene‐1,4‐diylidene) dimalononitrile (F4TCNQ) employed at the perovskite/hole transport layer (HTL) interfaces. Our findings reveal that EWMs simultaneously enhance chemical passivation, interface dipole effect, and chemically binding of the perovskite to the HTL. Notably, F4TCNQ, with its superior electron‐withdrawing properties, demonstrates a more pronounced impact. Consequently, PCSs modified with F4TCNQ achieved an impressive power conversion efficiency (PCE) of 25.21%, while demonstrating excellent long‐term stability. Moreover, the PCE of a larger‐area perovskite module (14.0 cm2) based on F4TCNQ reached 21.41%. This work illuminates the multifaceted mechanisms of EWMs at the interfaces in PSCs, delivering pivotal insights that pave the way for the sophisticated design and strategic application of EWMs, thereby propelling the advancement of perovskite photovoltaic technology

Unraveling the Role of Electron-Withdrawing Molecules for Highly Efficient and Stable Perovskite Photovoltaics.

Electron-withdrawing molecules (EWMs) have exhibited remarkable efficacy in boosting the performance of perovskite solar cells (PSCs). However, the underneath mechanisms governing their positive attributes remain inadequately understood. Herein, we conducted a comprehensive study on EWMs by comparing 2,2'-(2,5-cyclohexadiene-1,4-diylidene) bismalononitrile (TCNQ) and (2,3,5,6-tetrafluoro-2,5-cyclohexadiene-1,4-diylidene) dimalononitrile (F4TCNQ) employed at the perovskite/hole transport layer (HTL) interfaces. Our findings reveal that EWMs simultaneously enhance chemical passivation, interface dipole effect, and chemically binding of the perovskite to the HTL. Notably, F4TCNQ, with its superior electron-withdrawing properties, demonstrates a more pronounced impact. Consequently, PCSs modified with F4TCNQ achieved an impressive power conversion efficiency (PCE) of 25.21 %, while demonstrating excellent long-term stability. Moreover, the PCE of a larger-area perovskite module (14.0 cm2) based on F4TCNQ reached 21.41 %. This work illuminates the multifaceted mechanisms of EWMs at the interfaces in PSCs, delivering pivotal insights that pave the way for the sophisticated design and strategic application of EWMs, thereby propelling the advancement of perovskite photovoltaic technology.

Verification of modulation mechanism of the interfacial dipole effect by changing the stacking sequence of monatomic layers in perovskite oxides

The magnitude of the dipole effect detected by the cutoff energy measurement was modulated for SrTiO3 (STO)/LaAlO3 (LAO)/SrRuO3 (SRO)/STO (001) subs. epitaxial stacks by ultrathin SrAlOx (SAO) insertion prior to LAO deposition. The difference in frictional forces on the LAO surfaces between the stacks with and without SAO insertion was clearly detected by lateral force microscopy (LFM), which indicated the change in dominating surface atomic layers. From the statistical analysis of LFM images, the SAO insertion was found to improve the lateral uniformity of the stacking sequence of charged monatomic layers in epitaxial LAO along the c-axis [(LaO)+ and (AlO2)−], taking account of the inevitable correlation between the surface-terminating atoms with the stacking sequence of the charged monatomic layers in epitaxial LAO. These results are consistently explainable with the proposed model that the interface dipole effect along the c-axis of the perovskite epitaxial stack is determined by the stacking sequence of charged monatomic layers of LAO.

Opportunity for band alignment manipulation of perovskite oxide stacks by interfacial dipole layer formation

Dipole layers can be formed at epitaxial interfaces of perovskite oxides by intentionally inserting charged atomic layers. Perovskite oxides such as SrTiO3 (STO) can provide dielectrics with very high dielectric constants, but their bandgaps are so small that the suppression of leakage current is one of the critical issues when they are applied for DRAM capacitors. However, their conduction band offset will be manipulated if we can control the dipole layer formation. In this study, we investigated the opportunities of band alignment manipulation using the interface dipole effect especially focusing on the number of charge-introducing atomic layers. STO/LaAlO3 (LAO)/SrRuO3(SRO) stacks were fabricated by pulsed laser deposition method, to demonstrate the modulation of the band alignment at STO/SRO interface as large as ± 0.5 eV, when we change the number of inserted atomic layers of LAO.

Improvement of OLED performances by applying annealing and surface treatment on electro-deposited CuSCN hole injection layer

In this study, we demonstrated an organic light-emitting diode (OLED) using electro-deposited CuSCN as a hole-injection layer. The effects of thermal annealing and UV-Ozone treatments on ITO/CuSCN/organic interfaces were investigated. By employing both UV-O3 and proper thermal annealing (75 ° C, 20 min), Cu2O was found on the surface of CuSCN. With these treatments, the surface roughness of the organic deposited on CuSCN was reduced from 4.25 to 1.28 nm. The optical transmittance was also enhanced. Additionally, the CuSCN surface energy and polarity were considerably increased and the hole-injection barrier was decreased from 0.70 to 0.47 eV. The interface dipole effects lead to better adhesion between CuSCN/organic interface and facilitate the hole injection capability from anode ITO due to the formation of superficial Cu2O. The underlying mechanisms were illustrated by surface energy, X-Ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS) measurements. As a result, these significantly enhanced CuSCN characteristics led to improved OLED performances, which achieved a hundred-fold efficiency compared to the device without any treatment. With this realization of integrating electro-deposited CuSCN into conventional organic optoelectronic systems, it could bring various practical benefits particularly concerning industrial interests in low-temperature, cost-effective, and large-area fabrication techniques.

Inhomogeneous interface dipole effect at the Schottky junctions of PdCrO2 on β-Ga2O3 (2¯01) substrates

We report the lateral and vertical electrical conduction properties of PdCrO2 thin films grown on insulating Al2O3 (001) and conducting β-Ga2O3(2¯01) substrates. The c-axis oriented PdCrO2 films on the both substrates showed metallic temperature dependence of in-plane resistivity down to 2 K. In PdCrO2/β-Ga2O3 vertical devices, rectifying current density–voltage (J–V) characteristics revealed the formation of a Schottky barrier at the PdCrO2/β-Ga2O3 interface. The Schottky barrier height (SBH) of 1.2–1.8 eV, evaluated by J–V characteristics, is significantly larger than 0.8 eV expected from the usual Mott–Schottky relation based on the electron affinity of β-Ga2O3 (4.0 eV) and the work function of PdCrO2 (4.8 eV) determined by ultraviolet photoelectron spectroscopy. The enhanced SBH at the PdCrO2/β-Ga2O3 interface indicates the existence of interface dipoles, as in the case of PdCoO2/β-Ga2O3. Besides, we observed a large difference of the SBH between the J–V measurements (1.2–1.8 eV) and capacitance measurements (2.0–2.1 eV). While the SBH is definitely enhanced by the interface dipole effect, the level of enhancement at the PdCrO2/β-Ga2O3 interface is rather inhomogeneous, different from that at the PdCoO2/β-Ga2O3. In fact, two typical types of interfaces were found by a high-angle annular dark-field scanning transmission electron microscope, which would be the origin of the inhomogeneous SBH. Further understanding of the interface formation between delafossite oxides and β-Ga2O3(2¯01) will improve the performance of Ga2O3 Schottky junctions as a power diode available at high temperatures.

Control of Schottky barrier height in metal/β-Ga2O3 junctions by insertion of PdCoO2 layers

Control of Schottky barrier heights (SBHs) at metal/semiconductor interfaces is a critically important technique to design switching properties of semiconductor devices. In this study, we report the systematic variations of SBHs in metal/PdCoO2/β-Ga2O3 junctions with an increase in the thickness of the PdCoO2 insertion layer. The PdCoO2 insertion layer consists of ionic Pd+ and [CoO2]− sublattices alternatingly stacked along the normal of the Schottky interface. This polar layered structure of PdCoO2 spontaneously induces interface dipoles that increase the SBH in β-Ga2O3 devices. We fabricated Schottky junctions composed of metal/PdCoO2/β-Ga2O3 (−201) with the PdCoO2 thickness of 0–20 nm. With an increase in the PdCoO2 thickness, we observed a systematic shift of current density–voltage (J–V) characteristics to larger forward driving voltage. The shift of J–V characteristics indicates the enhancement of SBH by insertion of the PdCoO2 layer, which was confirmed by the capacitance measurement as the consistent shift of the built-in potential. These results demonstrate a controllable SBH in a wide range of 0.7–1.9 eV driven by a decisive contribution of the interface dipole effect. The Schottky junctions based on β-Ga2O3 with variable barrier heights could fit a wide range of applications, with the significant merits of optimizable switching properties.

Reduce the hysteresis effect with the PEIE interface dipole effect in the organic-inorganic hybrid perovskite CH3NH3PbI3-xClx solar cell

Abstract Power conversion efficiency (PCE) of CH3NH3PbI3 perovskite solar cells has been developed rapidly, it reached the 22.1%. However, the anomalous hysteresis found in I-V measurements can cause an inaccurate estimation of the efficiency. In this article, we fabricated the ITO/PEDOT:PSS/CH3NH3PbI3-xClx/ PCBM/PEIE/Al structure perovskite solar cell, we inserted an interface layer of Polyethylenimine ethoxylated (PEIE) into solar cell device between the PCBM and aluminum (Al) electrode, the electrical filed induce photoluminescence (PL) quenching experiment and capacitance-voltage characteristic both demonstrate that the PEIE layer exists an interface dipole effect in the perovskite solar cell device, it can effectively reduce the hysteresis effect in the I-V measurement, and greatly increase the solar cell's efficiency from the 10.93%–14.46%. Utilizing the photoinduction dielectric response technology, we further found that the interface dipole effect increased the built-in electrical field, and enhanced the charge carrier transport properties, consequently, increased the short-circuit current (Jsc). On the other hand, the interface dipole effect decreased the concentration of defect on the CH3NH3PbI3-xClx surface, and made the charge injection barrier to increasing at the electrode and perovskite interface, leading to enhance the open-circuit voltage (Voc). In addition, the diminution of defect could further increase more effective electron transport channels, leading to the more charge carriers transport toward to the corresponding electrode, and increased the solar cell's Fill Factor (FF). Therefore, the addition PEIE interface layer in the perovskite solar cell not only can remove the hysteresis effect but also develop the high PCE perovskite solar cell. We hope the interface dipole effect as an effective methods can greatly promote and develop high efficiency and stable perovskite solar cells.

High-efficiency solution-processed CdTe nanocrystal solar cells incorporating a novel crosslinkable conjugated polymer as the hole transport layer

Solution-processed nanocrystal (NC) solar cell are attracting much attention for prospective application in low cost energy source; however, the worse collection of hole carriers at the hole interface limits the device performance further improvement. Here, a novel crosslinkable conjugated polymer poly(diphenylsilane-co-4-vinyl-triphenylamine) (Si-TPA) has been applied as the hole transport layer (HTL) for solution-processed CdTe nanocrystal (NC) solar cells. To the best of our knowledge, it is the first report with a crosslinkable conjugated polymer as the HTL in NC solar cells. It is found that the devices with Si-TPA HTL show much better performance than that of the devices without the HTL or with other polymer HTLs such as poly(9-vinylcarbazole) (PVK) and poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). The improvement with incorporating Si-TPA is attributed to the better energy level matching between the NC film and the Au anode with a good ohmic contact among each interface. Interestingly, it is also observed that introducing Si-TPA can produce a higher open-circuit voltage compared to that without Si-TPA, originating from the interface dipole effect produced by Si-TPA. The improved fill factor value illustrates that the hole and electron carriers are more balanced in the devices with Si-TPA. The champion solar cell with a configuration of ITO/ZnO/CdSe/CdTe/Si-TPA/Au shows a PCE of 8.34%, which is a record for solution-processed CdTe NC solar cells to date with an inverted device structure. Furthermore, for another type of the solution-processed CdS NC device, a high PCE of 7.27% is also obtained with incorporating crosslinkable Si-TPA HTL, which is two times higher than that without Si-TPA, demonstrating the remarkable universality through this method. This work provides a new facile strategy in further increasing solution-processed NC solar cells performance by incorporating organic crosslinkable conjugated polymers as the HTL.

Tuning electrical properties of Au/n-InP junctions by inserting atomic layer deposited Al2O3 layer

In order to modulate the electrical properties of Au/n-InP contacts, the insertion of an Al2O3 layer deposited by atomic layer deposition (ALD) was employed. All the samples with an Al2O3 layer showed the increased barrier height compared to the sample without Al2O3 layer. The barrier height was also found to be almost constant regardless of the Al2O3 thickness. Analysis on the reverse bias current revealed that the dominant current transport is Poole-Frenkel emission for all the samples with an Al2O3 layer, indicating that the defects are generated in the Al2O3 layer. Our results suggest that the metal induced gap states (MIGS) or interface dipole effects did not play major role in the Au/Al2O3/InP junction properties. Rather, the removal of native oxide and the termination of dangling bonds by ALD process determined the modulation of barrier heights.

Emerging interface dipole versus screening effect in copolymer/metal nano-layered systems

Despite to the importance on the charge carrier injection and transport at organic/metal interface, there is yet an incomplete estimation of the various contribution to the overall dipole. This work shows how the mapping of the surface potential performed by Kelvin Probe Force Microscopy (KPFM) allows the direct observation of the interface dipole within an organic/metal multilayered structure. Moreover, we show how the sub-surface sensitivity of the KPFM depends on the thickness and surface coverage of the metallic layer. This paper proposes a way to control the surface potential of the exposed layer of an hybrid layered system by controlling the interface dipole at the organic/metal interface as a function of the nanometer scale thickness and the surface coverage of the metallic layer.We obtained a layered system constituted by repeated sequence of a copolymer film, poly(n-butylacrylate)-b-polyacrilic acid, and Au layer. We compared the results obtained by means of scanning probe microscopy technique with the results of the KPFM technique, that allows us to obtain high-contrast images of the underlying layer of copolymer behind a typical threshold, on the nanoscale, of the thickness of the metal layer. We considered the effect of the morphology of the gold layer on the covered area at different thicknesses by using the scanning electron microscopy technique.This finding represents a step forward towards the using of dynamic atomic force microscopy based characterization to explore the electrical properties of the sub-surface states of layered nanohybrid, that is a critical point for nanohybrid applications in sensors and energy storage devices.

Interface Dipole Effects as a Function of Molecular Tilt: Mechanical Gating of Electron Tunneling through Self-Assembled Monolayers?

Control of electron transport through molecular devices is a fundamental step toward design of functional molecular electronics. In this respect, the application of the field-effect transistor principle to molecular junctions appears to be a desirable strategy. Here we study the possibility of mechanically controlling the molecular orbital alignment in self-assembled monolayers via the electrostatic fields originating from dipoles at the metal–molecule interfaces. More specifically, we analyze first-principles simulations of prototype alkanedithiolate and alkanediamine monolayer junctions between Au(111) electrodes as a function of inclination of the molecules in the film. We find that the molecular orbital alignment and hence the low-bias conductance of the junctions, sensitively depends on the interface dipole. The dipole change with molecular tilt is rationalized in terms of two electrostatic effects: (i) the reorientation of a dipole associated with the anchoring group and (ii) a dipole modification arising from charge redistribution due to the metal–molecule bond. The first effect, dominating for the thiolates, is the desired way to gate the junctions by tuning of the molecular tilt. However, the second effect, equally important for the amines, may hamper the mechanical control of the level alignment because it depends on other geometric details than the tilt angle. Our results thus suggest that mechanical gating by tilt is achievable with molecules and anchoring groups with strong intrinsic dipole moments and well-defined binding geometry rather than with interface dipoles associated with weak and flexible metal–molecule bonds.

Theory of Covalent Adsorbate Frontier Orbital Energies on Functionalized Light-Absorbing Semiconductor Surfaces.

Functional hybrid interfaces between organic molecules and semiconductors are central to many emerging information and solar energy conversion technologies. Here we demonstrate a general, empirical parameter-free approach for computing and understanding frontier orbital energies - or redox levels - of a broad class of covalently bonded organic-semiconductor surfaces. We develop this framework in the context of specific density functional theory (DFT) and many-body perturbation theory calculations, within the GW approximation, of an exemplar interface, thiophene-functionalized silicon (111). Through detailed calculations taking into account structural and binding energetics of mixed-monolayers consisting of both covalently attached thiophene and hydrogen, chlorine, methyl, and other passivating groups, we quantify the impact of coverage, nonlocal polarization, and interface dipole effects on the alignment of the thiophene frontier orbital energies with the silicon band edges. For thiophene adsorbate frontier orbital energies, we observe significant corrections to standard DFT (∼1 eV), including large nonlocal electrostatic polarization effects (∼1.6 eV). Importantly, both results can be rationalized from knowledge of the electronic structure of the isolated thiophene molecule and silicon substrate systems. Silicon band edge energies are predicted to vary by more than 2.5 eV, while molecular orbital energies stay similar, with the different functional groups studied, suggesting the prospect of tuning energy alignment over a wide range for photoelectrochemistry and other applications.

Zero interface dipole induced threshold voltage shift of HfO2/SiO2 gate dielectric stacks with NH3 plasma treatment

NH3 plasma treatment on interfacial SiO2 to reduce the interface dipole effect.Energy band diagram of HfO2 films established by XPS and UV-VIS.Band-gap increase due to tetragonal phase of nitrogen doped HfO2 examined by XRD.Negligible oxygen ions movement between HfO2/nitrided SiO2 for zero dipole interface. The NH3 plasma treatment on interfacial SiO2 has been proposed to reduce the interface dipole effect of HfO2/SiO2 gate dielectric stacks. The X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectroscopy (UV-VIS) were used to establish the band diagram of the HfO2 films. The tetragonal crystallization phase of the HfO2 films examined by X-ray diffraction (XRD) was responsible for the band-gap increase during the NH3 plasma treatment. By using the Schottky emission and Fowler-Nordheim (F-N) tunneling, the effective electron barrier height of the Al/HfO2 gate stacks can be determined. Thus, the interface dipole and Fermi-level pinning induced flat-band voltage shifts of the Al/HfO2/SiO2/p-Si structure subjected to different NH3 plasma treatment conditions were obtained. It was found that the NH3 plasma treatment for about 4min was sufficient for achieving the zero dipole interface of the HfO2/SiO2 gate dielectric stack due to the negligible movement of the oxygen ions between the HfO2 and the nitrided oxide.

Photoemission study of the Si(1 1 1)-native SiO2/copper phthalocyanine (CuPc) ultra-thin film interface

The Ultraviolet and X-ray Photoemission Spectroscopy (UPS, XPS) investigation was done to examine the interface formation between deposited copper phthalocyanine (CuPc) thin films and covered with native oxide n- and p-type silicon Si(111) substrates. The UPS results indicated the existence of small interface dipole effect for very first layer of CuPc deposited on both types of substrates. The dipoles were oriented differently depending on silicon conductivity type. In this paper we present that near the inorganic/organic interface the phthalocyanine’s molecular orbital levels shift downwards 0.20±0.05eV in the case of n-Si substrate and upwards 0.25±0.05eV for p-Si indicating the different displacement of the negative charge within the interface region. This tendency was also confirmed by conducted XPS study of the core levels. It is highly probable that band bending-like shift is provoked by the continuous change of CuPc molecule orientation induced by interface polarization layer.

Interface dipole effect on thin film ferroelectric stability: First-principles and phenomenological modeling

Utilization of the switchable spontaneous polarization of ferroelectric materials offers a promising avenue for the future of nanoelectronic memories and logic devices provided that nanoscale metal-ferroelectric-metal heterostructures can be engineered to maintain a bi-stable polarization switchable by an applied electric field. The most challenging aspect of this approach is to overcome the deleterious interface effects which tend to render ferroelectric polarization either unstable or unswitchable and which become ever more important as ferroelectric materials are produced thinner and thinner. Here we use first-principles density functional calculations and phenomenological modeling to demonstrate that a BaO/RuO${}_{2}$ interface termination sequence in SrRuO${}_{3}$/BaTiO${}_{3}$/SrRuO${}_{3}$ epitaxial heterostructures grown on SrTiO${}_{3}$ can lead to a nonswitchable polarization state for thin BaTiO${}_{3}$ films due to a fixed interface dipole. The unfavorable interface dipole at the BaO/RuO${}_{2}$ interface leads to a strong preference for one polarization state and, in thin film structures, leads to instability of the second state below a certain critical thickness, thereby making the polarization unswitchable. We analyze the contribution of this interface dipole to the energetic stability of these heterostructures. Furthermore, we propose and demonstrate that this unfavorable interface dipole effect can be alleviated by deposition of a thin layer of SrTiO${}_{3}$ at the BaO/RuO${}_{2}$ terminated interface. Our first-principles and phenomenological modeling predict that the associated change of the interface termination sequence to SrO/TiO${}_{2}$ on both sides of the heterostructure leads to a restoration of bi-stability with a smaller critical thickness, along with an enhancement of the barrier for polarization reversal. These results demonstrate that interface engineering is a viable approach to enhance ferroelectric properties at the nanoscale.

ZnTe/GaAs(2 1 1)B heterojunction valence band discontinuity measured by X-ray photoelectron spectroscopy

Thin ZnTe layers were grown by molecular beam epitaxy on single crystal GaAs(211)B substrates. Reflection high energy electron diffraction monitored the deoxidation of substrate and entire growth process. Valence band offset was calculated with X-ray photoelectron spectroscopy. Also interface formation of the ZnTe/GaAs was studied. Analysis shows that interface is abrupt and calculated valance band offset is 0.25±0.1eV and indicates type I alignment. The experimental result agrees well with the theoretical predictions involving interface dipole effect as well as electron affinity rule.

Photoemission Spectroscopy of Tethered CdSe Nanocrystals: Shifts in Ionization Potential and Local Vacuum Level As a Function of Nanocrystal Capping Ligand

We report the characterization of the frontier orbital energies and interface dipole effects for bare and ligand-capped 3.6 and 6.0 nm diameter CdSe nanocrystals (NC) tethered to smooth gold substrates, using He(I) and He(II) UV photoemission spectroscopy. Changes in the ionization potential (IP) of the NCs and local effective work function of the films were explored as a function of the dipolar nature of the NC capping ligands. The addition of thiol-capping ligands 1-hexanethiol, 1-benzenethiol, and 4-fluorothiophenol to both sizes of NCs produces negligible shifts in energy offset between the high kinetic energy edge of the CdSe NCs and the gold substrate Fermi energy. However, the local vacuum level and IP of the nanocrystal layer are altered by as much as 0.3 eV. We demonstrate the importance of determining both the local vacuum level and the high kinetic energy edge of a tethered NC sample. These studies demonstrate a method that can be used in the future to characterize the frontier orbital energy offsets for modified or unmodified nanocrystalline films, in which the NCs are incorporated into host materials, for applications ranging from photovoltaics to light-emitting diodes.

The Effect of Random Dopant Fluctuation on Specific Contact Resistivity

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> An analytical model is developed to describe the effect of random dopant fluctuation (RDF) on specific contact resistivity <formula formulatype="inline"><tex Notation="TeX">$\rho_{c}$</tex></formula>. This model accounts for Schottky-barrier (SB) lowering due to image force, interface dipole, and bandgap narrowing effects and is calibrated to TCAD models and previously published experimental results. The contact parameters considered are contact area, SB height, and dopant concentration. The presented analysis suggests that <formula formulatype="inline"><tex Notation="TeX">$\rho_{c}$</tex> </formula> variation due to RDF will not be significant up to the end of the CMOS roadmap. </para>

Work function control of hole-selective polymer/ITO anode contacts: an electrochemical doping study

We present a novel method for electrodeposition of ultra-thin films of poly-3-hexylthiophene (e-P3HT) on chemically modified indium-tin oxide (ITO) electrodes, to produce a hole-selective contact with an easily tuned work function (Φ), as demonstrated by a combination of spectroelectrochemistry and ultraviolet photoemission spectroscopy (UPS). Selective contacts for optimized charge injection have become essential components for both thin film organic light emitting diodes (OLEDs) and organic photovoltaics (OPVs). Electrochemically doped e-P3HT thin films, using counter ions such as PF6− do not suffer from stability issues associated with more “acidic” polymer layers (e.g. PEDOT:PSS). By controlling the oxidation state of the e-P3HT film via electrochemical doping we control the charge density within the film, resulting in an increase in work function with an increase in degree of oxidation. The method of electrochemical formation and doping of the e-P3HT film, using either constant potential step (CA) versus pulsed-potential step (PPS) protocols, has a significant secondary impact on the work function, as a result of the interface dipole effects from entrapment of these counter ions in the near-surface region of the polymer film. These results have significance for the performance of both OLEDs and OPVs built on these doped e-P3HT layers.