What’s new in Version 5.9?

(Release date: June 03).

Graphs of minority carrier lifetime and diffusion length should now work properly in equilibrium. In the past, these graphs suffered from a loss of precision, making them jagged.

The short description of some batch parameters (related to doping) were changed in the QuickBatch dialog to improve clarity.

What’s new in Version 5.8?

(Release date: Dec 02).

A bug in the velocity saturation code was fixed. This meant that the mobility reduction at high fields was being overestimated by a factor of about two. This bug did not apply when 'total velocity saturation' was selected.

What’s new in Version 5.7?

(Release date: July 02).

One minor new feature has been added, which will only be of interest to programmers.

There is a new command-line option /g which allows PC1D to be run from an external program.

PC1D /g filename.prm opens the parameter file ‘filename.prm’ silently, runs the simulation, copies the contents of the interactive graph to the clipboard, and then exits. Note that if the PRM file had a one-line batch file associated with it, you could modify the batch file before running PC1D in order to change a model parameter.

Changes introduced in Version 5.6

(Release date: Sept 01).

Rear surface texturing now works. A bug in all previous versions was causing rear surface texturing to be applied at the front instead of the rear.

A new graphable function, ‘Pri-Surface Total reflectance’ has been added, to make it easier to match experimental reflectance data. The Quantum Efficiency graph now displays this total reflectance, instead of separate curves for front reflectance and escape.

BUGFIX: The batch commands for bandgaps were muddled up (Bandgap, AbsEd1, AbsEd2, AbsEi1, AbsEi2).

Changes introduced in Version 5.5

(Release date: Aug 00).

An error in the diffusion length graph has been fixed, and the limitations on mobility have been relaxed, allowing simulations of very low mobility cells. Some minor typographical errors in the numerical method section of the help file have been corrected.

In rare circumstances, previous versions of PC1D 5 would crash when exiting. This problem has been fixed.

Changes introduced in Version 5.4

(Release date: June 00).

·BUGFIX: Under certain circumstances, quantum efficiency calculations would not converge at long wavelengths. (This was due to a compiler bug, and only occurred in PC1D 5.3). This problem has been fixed.

·Graphs now look better when the PC1D window is only occupying part of your screen. The graphs remain readable down to small window sizes.

·A ‘reflectance’ shortcut button has been added to the toolbar, as a convenient way of adjusting the device reflectance.

No simulation results are affected by any of these changes.

New features introduced in Version 5.3 - Major batch enhancements

Internal Batch mode (‘QuickBatch’ button on toolbar)

A batch run can now be generated from inside PC1D, without having to use an external spreadsheet program. Just specify which parameters you want to vary, and over what range, and PC1D will do the rest.

Graphs saved between simulations

PC1D now saves graphs from the last 100 simulations. You can access them by pressing PageUp and PageDown in the Interactive Graph View. This is especially useful for batch runs: if you run a batch where only one parameter is varying, by pressing PgUp and PgDn, you can graphically see the effect of varying that parameter.

Increased speed (again!) – Now twice as fast as version 5.0 !

With the new models turned off, PC1D is now five times as fast as version 4.6, or seventeen times as fast as the old DOS version (PC-1D 3.3). With the new models turned on, it is fourteen times faster than the DOS version.

Parameter view displays more information

Values for recombination, applied circuit, light intensity, series resistance, etc are now displayed in the parameter screen. This will help ensure that you are performing the simulation that you intended. It also uses subscripts and superscripts to aid readability.

Slight convergence improvement

Some poorly-behaved problems will now converge, due to improved numerical precision in some of PC1D’s internal functions.

Minor features

·Light intensity limit increased: Some characterisation techniques using laser pulses result in extremely high light intensity. These situations can now be simulated.

·If you stop a simulation, change the light sources, and continue the simulation, PC1D will now recalculate the photogeneration before continuing.

·New graphable function, ‘IQE adjusted for light bias’, to easily obtain the quantum efficiency of a device which is being illuminated by a secondary (constant) light source.

·New shortcut batch parameters (BulkTau, FrS, RrS, FrIntRefl, RrIntRefl).

Changes introduced in Version 5.2

(Release date: Sept 98).

Bugfix - deleting batch files could cause PC1D to crash

Previous versions of PC1D didn’t check whether batch files had been deleted. PC1D would crash at the end of a simulation if the batch file had been deleted. This problem has now been fixed.

Bugfix - batch files with many parameters didn’t always work

Version 5.1 didn’t always work properly for batch files with more than about 18 parameters. It will now work properly with up to 30 parameters.

Better use of exponential notation

·Dialog boxes now use exponential notation for large values, instead of (cumbersome) fixed-point notation. For example, 43000000000 is now displayed as 4.3e10. This is particularly helpful for parameters such as intrinsic carrier concentration.

·The range for which scientific notation (rather than fixed point) is used can be changed from a new Options dialog box in the Options menu. It will affect dialog boxes, as well as the parameter view.

Numerical method described in help files

The numerical method used by PC1D is now described in detail in the help files.

Changes introduced in Version 5.1

(Release date: Mar 98).

Parameter View font selection

·The font to be used for the parameter view can now be selected (select Font in the Options menu). If you have a large screen, you may want to select a smaller font.

Better batch files

·There is now no intrinsic limit to the length of a batch file. Previously, batch files were limited to 100 lines. The maximum number of lines now depends on the operating system you are using. In Windows 95, batch files are limited to a few hundred lines (more if smaller font sizes are used in Parameter View). This limitation doesn’t apply to Windows NT, and Microsoft will probably fix the problem for Windows 98.

·Batch files can now have 30 fields across (although only the first 12 will print on A4 paper, unless you select a very small font size or copy the results into a spreadsheet program).

Increased speed (again!)

·Simulation speed is now three times as fast as PC1D 4.6, or eight times as fast as PC1D 3.6. On a 200Mhz Pentium, an IV curve for a simple cell now takes slightly less than 1 second.

Non-convergent problems

·PC1D is now much better at detecting non-convergent problems. If it detects a problem it can’t solve, it will stop immediately. It won’t display bad numerics in graphs.

·The annoying 1 second delay when trying to stop a non-convergent problem has been dramatically reduced.

Minor bug fixes

·Copying batch file data to clipboard would occasionally add a line of garbage at the end. This has been fixed.

·The program was always disabling rear external photogeneration files when reloading. It now saves and loads correctly.

·The mouse didn’t work well with non-simple curves in interactive graphs. For example, if you were sweeping voltage from +ve to -ve, it was not possible to select points with the mouse. Also, Voc, Isc and Pmax weren’t always displayed. These problems have now been fixed.

Changes introduced in Version 5.0

Version 5 is the first 32-bit (Windows 95 / Windows NT) version of PC1D. It will also run on Windows 3.1 if Win32s is installed (Win32s 1.71 or later is required). It was released on 8 Sept 97. The new features are:

Increased speed

·Simulation speed is now twice as fast!

Trap-assisted tunnelling

·Trap-assisted tunnelling can now be modelled using the Hurkx model for field-enhanced recombination. Access it through the Device:Material:Recombination dialog box.

Experimental data graphs

·External files of experimental data can be displayed simultaneously with simulation results. This makes it much simpler to fit simulation parameters to experimental results.

Increased simulation domain

·Extra batch parameters for shunt elements, contact positions, bandgap, and intrinsic concentration.

·Internal reflection can now be set to 100% (it was previously limited to 99%).

Better graphs

·All graphs can now be user-defined. You can redefine any of the existing graphs by (a) using the Define command in the Graph menu; or (b) double-clicking in the border area of any interactive graph.

·The graphs you select in the Four-graphs view and Interactive graph view are now saved with the excitation and parameter files. This is particularly helpful for IQE scans, etc, because it means you don’t have to redefine your graphs every time you restart PC1D. It also saves your auxiliary and experimental data graphs.

·In interactive graph view, press CTRL+arrow keys to move the caret rapidly.

User interface enhancements

·Support for long filenames.

·Minor features such as ToolTips for toolbar buttons.

·Tabbed dialog boxes! Many of the old dialog boxes were combined into tabbed dialogs, so the menu structure is now much simpler and less daunting. This is a particularly big improvement for reflectance, and for light sources.

·The parameter view no longer flickers while running a simulation. (This is one contributor to the increased speed).

Backwards compatibility

·Loads files created by any previous version of PC1D

·Option to save material, device, excitation and parameter files in a form that allows them to be read by PC1D 4.5 (Of course, any new features will be lost when saved in the old version). This option appears in all of the “Save As” dialog boxes.

Minor changes and bug fixes

·The program now gives correct results for rear illumination of a device made from more than one material.

·External files of absorption data are now interpolated logarithmically rather than linearly.

Changes introduced in Version 4.6

Version 4.6 was a very minor maintenance release, fixing an error which occured when ni was small, such as with large bandgap materials at low temperature. In such cases, the program erroneously introduced a large resistance at the contacts.

Changes introduced in Version 4.5

Version 4.5 was a minor maintenance release, fixing a few problems which were discovered after the release of 4.4:

·The list of recently used files under the File menu now works properly.

·The program now gives correct results when monochromatic light is used with zero intensity (such as happens when simulating the transient response to a laser pulse).

·The default values for free-carrier absorption in silicon now match the values recommended in the help file.

·A few more parameters can now be used in batch files: shunt elements, bandgap and intrinsic concentration.

·The file locations “Problem Parameters” external file path was removed, as it was not used by the program. The initial location for .PRM files should be set using the standard Windows “Properties” function (in Win 3.1, select the icon and press SHIFT+Enter).

Changes introduced in Version 4.4

4.4 was a minor maintenance release (Release date: Dec 96).

The silicon material parameters were updated to be consistent.

Also, a few minor bugs were fixed. E.g. in the device schematic, diodes are now displayed the correct way around.

New features introduced in Version 4.3 - Device diagram, free-carrier absorption, and total velocity saturation.

Version 4.3 was a major release (Release date: Oct 96).

In addition to minor bug fixes and improvements to the online help, the following new features were incorporated into PC1D Version 4.3:

User interface enhancements

·A diagram of the device is now displayed in the Parameter View, providing visual feedback of doping, texturing, and internal shunt elements. This makes it much easier to recognize mistakes when designing complex devices. You can also double-click on parts of the diagram to change them, which gives another method for setting up parameters.

·The behaviour of the scroll bars has been improved.

Increased capacity

·The maximum number of timesteps has been increased to 200.


·The majority-carrier mobility model for silicon has been revised to be more accurate in the vicinity of room temperature. The model now agrees better with the 1981 data of Thurber et al.

·The band-to-band recombination coefficient for silicon was corrected from 9.5E-14 to 9.5E-15 cm3/s.

·The ratio of Nc/Nv for silicon was changed from 2.8 to 1.06 to be consistent with the “new” lower value of intrinsic carrier concentration of 1E10 cm-3 at 300K which is now in common use.

·Free-carrier absorption can now be modelled. This improves the accuracy of simulations of heavily-doped devices.

·Velocity saturation can now be modelled accurately. Previous versions only limited carrier velocity due to a high electric field. You can now limit the velocity due to both drift and diffusion. To do so, turn on Total velocity saturation in the Compute:Numerical dialog box. Note, however, that invoking this feature will significantly slow down your solution and is only recommended when this effect is important to your device. Normally, it will only affect heterostructures where the current is limited by thermionic emission over an energy barrier.

New features introduced in Version 4.2

(Release date: Aug 96).

Improved convergence

·Dynamic renoding was introduced into the solution code. This improves convergence of many problems, especially reverse bias and floating junctions.

·The internal equations were changed back to the old ones used in Version 3. It turns out that the old equations have superior convergence properties.

·8 extra plot functions were added.

Increased speed

·Photogeneration now 4 times faster. (Makes steady-state problems 25% faster overall).

New features introduced in Version 4.1

4.1 was a minor maintenance release (Release date: July 96).

Several bugs were fixed. In addition:

·You can now use a previously solved solution as a starting point for a new one, using the ‘Continue’ feature in the Compute menu.

·Width of batch files was increased to 12 parameters.

·A new plot function (Convergence Error) was added.

Version 4.0 – Initial Windows release

Version 4.0 was the first version of PC1D for Windows. It was showcased at the 25th IEEE Photovoltaics Specialist Conference in Washington DC, and publicly released in June 96. It replaced the DOS version, PC-1D version 3.3.