ν-DABNA-M-B-Mes

Structure

Selective late-stage double borylation changes the B/N resonance framework. The two standard TADF devices share an architecture; the separate sensitised comparison changes the device stack.

Properties and function

Spectral selectivity

Emission peak and linewidth are measured in a defined host film.

Molecular and device changes

A structural modification and a sensitised device architecture test different parts of the path to useful light.

Device and processing

1. Prepare the precursor

   Buchwald–Hartwig C–N coupling builds the aromatic precursor.

2. Control borylation sites

   Removable chlorine groups guide one-shot borylation; reductive dechlorination exposes the next sites.

3. Modify the emitter

   BI₃-mediated borylation followed by MesMgBr introduces additional boron sites.

Matched film measurements

1 wt% in PMMA; absolute PL quantum yield under N2.

Figure 4 labels spectra and decays at 300 K; methods state absorption/PL instruments operated at 298 K. No precision beyond the source is implied.

Difference of fluorescence and phosphorescence emission maxima at 77 K; phosphorescence delay 25 ms.

Authors inferred rate constants from quantum yields and fluorescence lifetimes; they are model-derived, not direct independent measurements.

No uncertainties supplied for the tabulated values.

From emitter to OLED

The modified emitter shows a 10 nm blue shift in the same PMMA-film conditions while retaining high PLQY.

At 1000 cd m−2 the modified emitter retains more of its peak EQE, but its directly excited TADF device has a shorter measured LT80.

Host, transport layers, sensitizer and emissive-layer thickness all change; differences are architecture-level associations, not an isolated sensitizer effect.

Standard TADF emitting layers: 1 wt% emitter in mCBP:DOBNA-Tol, 20 nm. PSF emitting layer: 1 wt% terminal emitter and 13 wt% PtON-TBBI in SiCzCz:SiTrzCz2, 35 nm. Host mixing ratios were not recovered from the accessible source.

EQE retention = 100 × EQE1000 / EQEmax. The chart points are published numeric figure labels, not raw spectra or a fitted device model.

Choose the brightness before ranking the blue OLEDs

All three devices have published numerical EQE labels at 10, 100 and 1000 cd m−2. Values below are discrete reported checkpoints; no missing point is interpolated and no full curve is reconstructed.

PSF-D3 minus TADF-D2: −5.5 pp at 10 cd m−2; −0.4 pp at 100 cd m−2; +5.5 pp at 1000 cd m−2. The sensitised device ranks below the standard TADF device at the first two checkpoints and above it at 1000 cd m−2. This does not establish an exact crossover luminance or statistical significance.

These are device-to-device EQE differences in percentage points, distinct from each device’s loss relative to its own peak. Matching luminance does not match current or excitation density, particularly when emission spectra differ. D2 versus D3 also changes host, sensitiser, transport layers and emitting-layer thickness.

Measured ageing conditions: TADF-D1, LT80 67 h from 100 cd m−2; TADF-D2, LT80 15 h from 100 cd m−2; PSF-D3, LT80 16 h from 1000 cd m−2. The different starting luminances prevent a direct D3/D2 lifetime ratio; the quoted 1010 h at 100 cd m−2 for D3 is an extrapolation.

• Hao et al. (2025), Figure 5: standard TADF devices
• Hao et al. (2025), Figure 6: sensitised device
• Hao et al. (2025), Table 2: measured lifetimes and device summaries

Measured operation and lifetime extrapolation

TADF-D2: LT80 = 15 h measured at initial luminance 100 cd m−2.

PSF-D3: LT80 = 16 h measured at initial luminance 1000 cd m−2. The 1010 h value at 100 cd m−2 is estimated using the assumed exponent n = 1.8; it is not a 1010-hour measurement.

For PSF-D3, LT80(100 cd m−2) = 16 × (1000/100)^1.8 = 1009.53 h, rounded to 1010 h by the authors. An exponent sensitivity sweep is an assumption test, not a confidence interval. Changing the device stack does not isolate a causal sensitizer effect.

Published molecular transformation

Buchwald–Hartwig amination assembles the arylamine precursor. Pd2(dba)3 / SPhos / sodium tert-butoxide; toluene, 80 °C, 4 h; reported isolated yield 82%.

Chlorine-directed borylation builds the B/N multiple-resonance framework. BI3; o-dichlorobenzene, 100 °C, 8 h; reported isolated yield 40%.

Reductive dechlorination gives ν-DABNA-M. NaBH4 / NiCl2(dppe); dimethylacetamide, 110 °C, 17 h; reported isolated yield 90%.

Late-stage double borylation followed by mesityl addition gives ν-DABNA-M-B-Mes. BI3; o-dichlorobenzene, 100 °C, 14 h; then mesitylmagnesium bromide, 40 °C, overnight; reported isolated yield 48%.

Scope of this analysis

PMMA photophysics and device-host electroluminescence are separate experiments.

Spectral peaks and widths are tabulated summaries, not downloadable raw spectra.

No statistically supported significance test is possible without replicates or uncertainty.

A two-molecule comparison cannot establish a general structure–property law.

Do not compare lifetime values at different starting luminances without stating the conversion assumptions.

Computed photon energy at an emission maximum is not a measured transport gap.

More conjugation does not guarantee a redshift; heteroatom position and resonance topology matter.

Displayed source values are rounded: the new emitter PLQY is 0.93 in Table 1 and 0.931 in the SI; reported rates are not exactly reconstructible from every rounded lifetime.

PMMA as a photoluminescence matrix

The PMMA record explains its carbon backbone, ester side groups, optical clarity and preparation from methyl methacrylate.

The 2025 emitter pair was measured in 1 wt% PMMA films. Here a familiar polymer holds the emitter while its optical response is measured.

The PMMA sample measures photoluminescence. Electrical device performance is measured using the OLED’s own host and layer structure.

• PMMA
• Methyl methacrylate
• Addition polymerisation
• Hao et al. — supplementary information

Organomagnesium functionalisation of boron

The current routes introduce organomagnesium chemistry through carbonyl addition and explain why the reaction stage needs dry conditions.

The published late-stage transformation uses BI3, followed by mesitylmagnesium bromide, to form the mesityl-substituted boron centres.

This step transfers an aryl group to boron.

• Grignard reagents
• Tetrahydrofuran
• Grignard addition to an aldehyde
• Hao et al. — supplementary information

Aryl halides in C–N coupling

Aryl C–halogen bonds and an aromatic amine are already represented as distinct molecular features.

The research syntheses assemble substituted arylamine precursors before constructing the boron-containing framework. The 2025 route uses Buchwald–Hartwig C–N coupling.

Aniline illustrates an aromatic amine; the published synthesis requires specifically substituted precursors and selective coupling conditions.

• Halogenoarenes
• Aniline
• Benzene bromination
• Nitrobenzene reduction
• Hu et al. — supplementary information
• Late-stage direct double borylation of B/N-based multi-resonance framework enables high-performance ultra-narrowband deep-blue organic light-emitting diodes

Conjugation and emission energy

Benzene and biphenyl provide concrete aromatic structures; the existing oligophenyl investigation examines one specific absorption trend.

The 2025 pair challenges a simple longer-conjugation/redder-emission rule: precisely placed additional boron changes the electronic pattern and gives a blue shift.

The oligophenyl result concerns absorption in a different series. Emission energy, the frontier-orbital energy difference and the singlet–triplet gap are different quantities.

• Benzene
• Biphenyl
• Boron
• Late-stage direct double borylation of B/N-based multi-resonance framework enables high-performance ultra-narrowband deep-blue organic light-emitting diodes
• Quantitative prediction of rate constants and its application to organic emitters

Sources and reproducible analysis

Published measurements, source-derived rates and Mol2Mat calculations are identified separately. The downloads reproduce the analysis without claiming new synthesis, device fabrication or electronic-structure calculations.

• Reproducibility bundle
• Analysis JSON
• Source manifest
• Python calculation
• Condition-annotated data
• Film measurements CSV
• Device measurements CSV
• Measured and estimated lifetimes CSV
• article
• photophysics-table
• devices-table
• supplement

Density-dependent excited-state losses

conditional-normalized-steady-state-model

All defaults are illustrative dimensionless assumptions; no rate is assigned to a selected BNOO, BNSS, BNSSe or BNSeSe emitter.

Spatially uniform, steady generation in a two-excited-state kinetic system. S1/T1 are coarse-grained states, not a reduction fitted to the separate S1/T1/T2 calculation.

Fixed first-order coefficients, no state filling, heating, diffusion gradients, charge transport, polaron annihilation, phosphorescence, singlet-singlet annihilation or chemical degradation.

fS=.25 is an assumed electrical 1:3 singlet:triplet generation fraction. fS=1 describes pure singlet generation, not an entire optical experiment.

TTA f=.25 is the stated effective branch convention. It is not a measured universal spin yield.

STA destroys one singlet and leaves one triplet after rapid higher-triplet relaxation.

Both a and b scale proportionally with G for a fixed material; changing only one load is a channel-isolation counterfactual.

The interactive comparison varies dimensionless generation load kTT G / KS² and scales kST G / KS² with it. The two-state sensitivity model is separate from the material-specific three-state calculation. It does not convert a measured OLED curve into collision-rate constants.

kTT*T^2 is effective annihilating encounters per volume per time. At f=1/4 the singlet source is +(1/4)kTT*T^2 and triplet sink is -(5/4)kTT*T^2. The NET excitation-number loss is kTT*T^2, not 2*kTT*T^2.

• Reproducible density-loss calculation
• Density scenarios and method limits

An operando test of competing mechanisms, 2026

King et al., Uncovering the Origin of Efficiency Roll-Off in TADF OLEDs. 15 wt% 4CzIPN in mCBP; 30 nm emissive layer.

TTA was negligible in this device; STA and polaron quenching explained the measured roll-off.

SPA dominated below about 100 mA cm^-2.

STA dominated above about 100 mA cm^-2.

The adjacent normalised TTA/STA exercise is a sensitivity calculation. It neither uses these fitted coefficients as presets nor reproduces the measured 4CzIPN device, which also requires SPA, TPA, charge densities and device geometry.

The ± values below are one standard deviation from fitting. An additional estimated 20% uncertainty in generation rate is excluded. The TTA upper bound is based on the fit’s 95% confidence interval. No independent reprocessing of the source raw dataset is claimed.

• Uncovering the Origin of Efficiency Roll-Off in TADF OLEDs
• Published experimental dataset record

Evidence and limits

Matched 2025 film and device measurements are compared directly, with lifetime projections separated from measured operation.

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References

• Nature Communications 16, 8867 (2025) · Paper and supplementary information